Selectables, Tables, FROM objects — SQLAlchemy 1.1 Documentation

Release: 1.1.18 | Release Date: March 6, 2018

# SQLAlchemy 1.1 Documentation

# Selectables, Tables, FROM objects

The term “selectable” refers to any object that rows can be selected from; in SQLAlchemy, these objects descend from `FromClause` and their distinguishing feature is their `FromClause.c` attribute, which is a namespace of all the columns contained within the FROM clause (these elements are themselves `ColumnElement` subclasses).

`sqlalchemy.sql.expression.` `alias`(selectable, name=None, flat=False)

  Return an `Alias` object.

  An `Alias` represents any `FromClause` with an alternate name assigned within SQL, typically using the `AS` clause when generated, e.g. `SELECT * FROM table AS aliasname`.

  Similar functionality is available via the `alias()` method available on all `FromClause` subclasses.

  When an `Alias` is created from a `Table` object, this has the effect of the table being rendered as `tablename AS aliasname` in a SELECT statement.

  For `select()` objects, the effect is that of creating a named subquery, i.e. `(select ...) AS aliasname`.

  The `name` parameter is optional, and provides the name to use in the rendered SQL. If blank, an “anonymous” name will be deterministically generated at compile time. Deterministic means the name is guaranteed to be unique against other constructs used in the same statement, and will also be the same name for each successive compilation of the same statement object.

  Parameters: | selectable – any `FromClause` subclass, such as a table, select statement, etc. name – string name to be assigned as the alias. If `None`, a name will be deterministically generated at compile time. flat – Will be passed through to if the given selectable is an instance of `Join` - see `Join.alias()` for details. New in version 0.9.0.

`sqlalchemy.sql.expression.` `except_`(*selects, **kwargs)

  Return an `EXCEPT` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.` `except_all`(*selects, **kwargs)

  Return an `EXCEPT ALL` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.` `exists`(*args, **kwargs)

  Construct a new `Exists` against an existing `Select` object.

  Calling styles are of the following forms:

      # use on an existing select()
      s = select([table.c.col1]).where(table.c.col2==5)
      s = exists(s)

      # construct a select() at once
      exists(['*'], **select_arguments).where(criterion)

      # columns argument is optional, generates "EXISTS (SELECT *)"
      # by default.
      exists().where(table.c.col2==5)

`sqlalchemy.sql.expression.` `intersect`(*selects, **kwargs)

  Return an `INTERSECT` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.` `intersect_all`(*selects, **kwargs)

  Return an `INTERSECT ALL` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.` `join`(left, right, onclause=None, isouter=False, full=False)

  Produce a `Join` object, given two `FromClause` expressions.

  E.g.:

      j = join(user_table, address_table,
               user_table.c.id == address_table.c.user_id)
      stmt = select([user_table]).select_from(j)

  would emit SQL along the lines of:

      SELECT user.id, user.name FROM user
      JOIN address ON user.id = address.user_id

  Similar functionality is available given any `FromClause` object (e.g. such as a `Table`) using the `FromClause.join()` method.

  Parameters: | left – The left side of the join. right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of JOIN. New in version 1.1.

  See also

  `FromClause.join()` - method form, based on a given left side

  `Join` - the type of object produced

`sqlalchemy.sql.expression.` `lateral`(selectable, name=None)

  Return a `Lateral` object.

  `Lateral` is an `Alias` subclass that represents a subquery with the LATERAL keyword applied to it.

  The special behavior of a LATERAL subquery is that it appears in the FROM clause of an enclosing SELECT, but may correlate to other FROM clauses of that SELECT. It is a special case of subquery only supported by a small number of backends, currently more recent PostgreSQL versions.

  New in version 1.1.

  See also

  LATERAL correlation - overview of usage.

`sqlalchemy.sql.expression.` `outerjoin`(left, right, onclause=None, full=False)

  Return an `OUTER JOIN` clause element.

  The returned object is an instance of `Join`.

  Similar functionality is also available via the `outerjoin()` method on any `FromClause`.

  Parameters: | left – The left side of the join. right – The right side of the join. onclause – Optional criterion for the `ON` clause, is derived from foreign key relationships established between left and right otherwise.

  To chain joins together, use the `FromClause.join()` or `FromClause.outerjoin()` methods on the resulting `Join` object.

`sqlalchemy.sql.expression.` `select`(columns=None, whereclause=None, from_obj=None, distinct=False, having=None, correlate=True, prefixes=None, suffixes=None, **kwargs)

  Construct a new `Select`.

  Similar functionality is also available via the `FromClause.select()` method on any `FromClause`.

  All arguments which accept `ClauseElement` arguments also accept string arguments, which will be converted as appropriate into either `text()` or `literal_column()` constructs.

  See also

  Selecting - Core Tutorial description of `select()`.

  Parameters: | columns – A list of `ColumnElement` or `FromClause` objects which will form the columns clause of the resulting statement. For those objects that are instances of `FromClause` (typically `Table` or `Alias` objects), the `FromClause.c` collection is extracted to form a collection of `ColumnElement` objects. This parameter will also accept `Text` constructs as given, as well as ORM-mapped classes. Note The `select.columns` parameter is not available in the method form of `select()`, e.g. `FromClause.select()`. See also `Select.column()` `Select.with_only_columns()` whereclause – A `ClauseElement` expression which will be used to form the `WHERE` clause. It is typically preferable to add WHERE criterion to an existing `Select` using method chaining with `Select.where()`. See also `Select.where()` from_obj – A list of `ClauseElement` objects which will be added to the `FROM` clause of the resulting statement. This is equivalent to calling `Select.select_from()` using method chaining on an existing `Select` object. See also `Select.select_from()` - full description of explicit FROM clause specification. autocommit – Deprecated. Use `.execution_options(autocommit=<True|False>)` to set the autocommit option. See also `Executable.execution_options()` bind=None – an `Engine` or `Connection` instance to which the resulting `Select` object will be bound. The `Select` object will otherwise automatically bind to whatever `Connectable` instances can be located within its contained `ClauseElement` members. correlate=True – indicates that this `Select` object should have its contained `FromClause` elements “correlated” to an enclosing `Select` object. It is typically preferable to specify correlations on an existing `Select` construct using `Select.correlate()`. See also `Select.correlate()` - full description of correlation. distinct=False – when `True`, applies a `DISTINCT` qualifier to the columns clause of the resulting statement. The boolean argument may also be a column expression or list of column expressions - this is a special calling form which is understood by the PostgreSQL dialect to render the `DISTINCT ON (<columns>)` syntax. `distinct` is also available on an existing `Select` object via the `distinct()` method. See also `Select.distinct()` for_update=False – when `True`, applies `FOR UPDATE` to the end of the resulting statement. Deprecated since version 0.9.0: - use `Select.with_for_update()` to specify the structure of the `FOR UPDATE` clause. `for_update` accepts various string values interpreted by specific backends, including: `"read"` - on MySQL, translates to `LOCK IN SHARE MODE`; on PostgreSQL, translates to `FOR SHARE`. `"nowait"` - on PostgreSQL and Oracle, translates to `FOR UPDATE NOWAIT`. `"read_nowait"` - on PostgreSQL, translates to `FOR SHARE NOWAIT`. See also `Select.with_for_update()` - improved API for specifying the `FOR UPDATE` clause. group_by – a list of `ClauseElement` objects which will comprise the `GROUP BY` clause of the resulting select. This parameter is typically specified more naturally using the `Select.group_by()` method on an existing `Select`. See also `Select.group_by()` having – a `ClauseElement` that will comprise the `HAVING` clause of the resulting select when `GROUP BY` is used. This parameter is typically specified more naturally using the `Select.having()` method on an existing `Select`. See also `Select.having()` limit=None – a numerical value which usually renders as a `LIMIT` expression in the resulting select. Backends that don’t support `LIMIT` will attempt to provide similar functionality. This parameter is typically specified more naturally using the `Select.limit()` method on an existing `Select`. See also `Select.limit()` offset=None – a numeric value which usually renders as an `OFFSET` expression in the resulting select. Backends that don’t support `OFFSET` will attempt to provide similar functionality. This parameter is typically specified more naturally using the `Select.offset()` method on an existing `Select`. See also `Select.offset()` order_by – a scalar or list of `ClauseElement` objects which will comprise the `ORDER BY` clause of the resulting select. This parameter is typically specified more naturally using the `Select.order_by()` method on an existing `Select`. See also `Select.order_by()` use_labels=False – when `True`, the statement will be generated using labels for each column in the columns clause, which qualify each column with its parent table’s (or aliases) name so that name conflicts between columns in different tables don’t occur. The format of the label is <tablename>_<column>. The “c” collection of the resulting `Select` object will use these names as well for targeting column members. This parameter can also be specified on an existing `Select` object using the `Select.apply_labels()` method. See also `Select.apply_labels()`

`sqlalchemy.sql.expression.` `subquery`(alias, *args, **kwargs)

  Return an `Alias` object derived from a `Select`.

  name
    alias name

  *args, **kwargs

  > all other arguments are delivered to the `select()` function.

`sqlalchemy.sql.expression.` `table`(name, *columns)

  Produce a new `TableClause`.

  The object returned is an instance of `TableClause`, which represents the “syntactical” portion of the schema-level `Table` object. It may be used to construct lightweight table constructs.

  Changed in version 1.0.0: `expression.table()` can now be imported from the plain `sqlalchemy` namespace like any other SQL element.

  Parameters: | name – Name of the table. columns – A collection of `expression.column()` constructs.

`sqlalchemy.sql.expression.` `tablesample`(selectable, sampling, name=None, seed=None)

  Return a `TableSample` object.

  `TableSample` is an `Alias` subclass that represents a table with the TABLESAMPLE clause applied to it. `tablesample()` is also available from the `FromClause` class via the `FromClause.tablesample()` method.

  The TABLESAMPLE clause allows selecting a randomly selected approximate percentage of rows from a table. It supports multiple sampling methods, most commonly BERNOULLI and SYSTEM.

  e.g.:

      from sqlalchemy import func

      selectable = people.tablesample(
                  func.bernoulli(1),
                  name='alias',
                  seed=func.random())
      stmt = select([selectable.c.people_id])

  Assuming `people` with a column `people_id`, the above statement would render as:

      SELECT alias.people_id FROM
      people AS alias TABLESAMPLE bernoulli(:bernoulli_1)
      REPEATABLE (random())

  New in version 1.1.

  Parameters: | sampling – a `float` percentage between 0 and 100 or `functions.Function`. name – optional alias name seed – any real-valued SQL expression. When specified, the REPEATABLE sub-clause is also rendered.

`sqlalchemy.sql.expression.` `union`(*selects, **kwargs)

  Return a `UNION` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  A similar `union()` method is available on all `FromClause` subclasses.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.` `union_all`(*selects, **kwargs)

  Return a `UNION ALL` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  A similar `union_all()` method is available on all `FromClause` subclasses.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

class `sqlalchemy.sql.expression.` `Alias`(selectable, name=None)

  Bases: `sqlalchemy.sql.expression.FromClause`

  Represents an table or selectable alias (AS).

  Represents an alias, as typically applied to any table or sub-select within a SQL statement using the `AS` keyword (or without the keyword on certain databases such as Oracle).

  This object is constructed from the `alias()` module level function as well as the `FromClause.alias()` method available on all `FromClause` subclasses.

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(name=None, flat=False)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `description`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `get_children`(column_collections=True, **kw)

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `is_derived_from`(fromclause)

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(target=None)

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.` `CompoundSelect`(keyword, *selects, **kwargs)

  Bases: `sqlalchemy.sql.expression.GenerativeSelect`

  Forms the basis of `UNION`, `UNION ALL`, and other
    SELECT-based set operations.

  See also

  `union()`

  `union_all()`

  `intersect()`

  `intersect_all()`

  `except()`

  `except_all()`

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(name=None, flat=False)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `append_group_by`(*clauses)
    inherited from the `append_group_by()` method of `GenerativeSelect`

    Append the given GROUP BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing GROUP BY criterion.

    This is an in-place mutation method; the `group_by()` method is preferred, as it provides standard method chaining.

  `append_order_by`(*clauses)
    inherited from the `append_order_by()` method of `GenerativeSelect`

    Append the given ORDER BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing ORDER BY criterion.

    This is an in-place mutation method; the `order_by()` method is preferred, as it provides standard method chaining.

  `apply_labels`()
    inherited from the `apply_labels()` method of `GenerativeSelect`

    return a new selectable with the ‘use_labels’ flag set to True.

    This will result in column expressions being generated using labels against their table name, such as “SELECT somecolumn AS tablename_somecolumn”. This allows selectables which contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts among the individual FROM clauses.

  `as_scalar`()
    inherited from the `as_scalar()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, which can be used as a column expression.

    Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.

    The returned object is an instance of `ScalarSelect`.

  `autocommit`()
    inherited from the `autocommit()` method of `SelectBase`

    return a new selectable with the ‘autocommit’ flag set to True.

    Deprecated since version 0.6: `autocommit()` is deprecated. Use `Executable.execution_options()` with the ‘autocommit’ flag.

  `bind`

    Returns the `Engine` or `Connection` to which this `Executable` is bound, or None if none found.

    This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `cte`(name=None, recursive=False)
    inherited from the `cte()` method of `HasCTE`

    Return a new `CTE`, or Common Table Expression instance.

    Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.

    CTEs can also be applied to DML constructs UPDATE, INSERT and DELETE on some databases, both as a source of CTE rows when combined with RETURNING, as well as a consumer of CTE rows.

    SQLAlchemy detects `CTE` objects, which are treated similarly to `Alias` objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.

    Changed in version 1.1: Added support for UPDATE/INSERT/DELETE as CTE, CTEs added to UPDATE/INSERT/DELETE.

    Parameters: | name – name given to the common table expression. Like `_FromClause.alias()`, the name can be left as `None` in which case an anonymous symbol will be used at query compile time. recursive – if `True`, will render `WITH RECURSIVE`. A recursive common table expression is intended to be used in conjunction with UNION ALL in order to derive rows from those already selected.

    The following examples include two from PostgreSQL’s documentation at http://www.postgresql.org/docs/current/static/queries-with.html, as well as additional examples.

    Example 1, non recursive:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        orders = Table('orders', metadata,
            Column('region', String),
            Column('amount', Integer),
            Column('product', String),
            Column('quantity', Integer)
        )

        regional_sales = select([
                            orders.c.region,
                            func.sum(orders.c.amount).label('total_sales')
                        ]).group_by(orders.c.region).cte("regional_sales")

        top_regions = select([regional_sales.c.region]).\
                where(
                    regional_sales.c.total_sales >
                    select([
                        func.sum(regional_sales.c.total_sales)/10
                    ])
                ).cte("top_regions")

        statement = select([
                    orders.c.region,
                    orders.c.product,
                    func.sum(orders.c.quantity).label("product_units"),
                    func.sum(orders.c.amount).label("product_sales")
            ]).where(orders.c.region.in_(
                select([top_regions.c.region])
            )).group_by(orders.c.region, orders.c.product)

        result = conn.execute(statement).fetchall()

    Example 2, WITH RECURSIVE:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        parts = Table('parts', metadata,
            Column('part', String),
            Column('sub_part', String),
            Column('quantity', Integer),
        )

        included_parts = select([
                            parts.c.sub_part,
                            parts.c.part,
                            parts.c.quantity]).\
                            where(parts.c.part=='our part').\
                            cte(recursive=True)

        incl_alias = included_parts.alias()
        parts_alias = parts.alias()
        included_parts = included_parts.union_all(
            select([
                parts_alias.c.sub_part,
                parts_alias.c.part,
                parts_alias.c.quantity
            ]).
                where(parts_alias.c.part==incl_alias.c.sub_part)
        )

        statement = select([
                    included_parts.c.sub_part,
                    func.sum(included_parts.c.quantity).
                      label('total_quantity')
                ]).\
                group_by(included_parts.c.sub_part)

        result = conn.execute(statement).fetchall()

    Example 3, an upsert using UPDATE and INSERT with CTEs:

        from datetime import date
        from sqlalchemy import (MetaData, Table, Column, Integer,
                                Date, select, literal, and_, exists)

        metadata = MetaData()

        visitors = Table('visitors', metadata,
            Column('product_id', Integer, primary_key=True),
            Column('date', Date, primary_key=True),
            Column('count', Integer),
        )

        # add 5 visitors for the product_id == 1
        product_id = 1
        day = date.today()
        count = 5

        update_cte = (
            visitors.update()
            .where(and_(visitors.c.product_id == product_id,
                        visitors.c.date == day))
            .values(count=visitors.c.count + count)
            .returning(literal(1))
            .cte('update_cte')
        )

        upsert = visitors.insert().from_select(
            [visitors.c.product_id, visitors.c.date, visitors.c.count],
            select([literal(product_id), literal(day), literal(count)])
                .where(~exists(update_cte.select()))
        )

        connection.execute(upsert)

    See also

    `orm.query.Query.cte()` - ORM version of `HasCTE.cte()`.

  `description`
    inherited from the `description` attribute of `FromClause`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `execute`(*multiparams, **params)
    inherited from the `execute()` method of `Executable`

    Compile and execute this `Executable`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `for_update`
    inherited from the `for_update` attribute of `GenerativeSelect`

    Provide legacy dialect support for the `for_update` attribute.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `get_children`(column_collections=True, **kwargs)

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `group_by`(*clauses)
    inherited from the `group_by()` method of `GenerativeSelect`

    return a new selectable with the given list of GROUP BY criterion applied.

    The criterion will be appended to any pre-existing GROUP BY criterion.

  `is_derived_from`(fromclause)

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `label`(name)
    inherited from the `label()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.

    See also

    `as_scalar()`.

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `limit`(limit)
    inherited from the `limit()` method of `GenerativeSelect`

    return a new selectable with the given LIMIT criterion applied.

    This is a numerical value which usually renders as a `LIMIT` expression in the resulting select. Backends that don’t support `LIMIT` will attempt to provide similar functionality.

    Changed in version 1.0.0: - `Select.limit()` can now accept arbitrary SQL expressions as well as integer values.

    Parameters: | limit – an integer LIMIT parameter, or a SQL expression that provides an integer result.

  `offset`(offset)
    inherited from the `offset()` method of `GenerativeSelect`

    return a new selectable with the given OFFSET criterion applied.

    This is a numeric value which usually renders as an `OFFSET` expression in the resulting select. Backends that don’t support `OFFSET` will attempt to provide similar functionality.

    Changed in version 1.0.0: - `Select.offset()` can now accept arbitrary SQL expressions as well as integer values.

    Parameters: | offset – an integer OFFSET parameter, or a SQL expression that provides an integer result.

  `order_by`(*clauses)
    inherited from the `order_by()` method of `GenerativeSelect`

    return a new selectable with the given list of ORDER BY criterion applied.

    The criterion will be appended to any pre-existing ORDER BY criterion.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `scalar`(*multiparams, **params)
    inherited from the `scalar()` method of `Executable`

    Compile and execute this `Executable`, returning the result’s scalar representation.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(against=None)

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

  `with_for_update`(nowait=False, read=False, of=None, skip_locked=False, key_share=False)
    inherited from the `with_for_update()` method of `GenerativeSelect`

    Specify a `FOR UPDATE` clause for this `GenerativeSelect`.

    E.g.:

        stmt = select([table]).with_for_update(nowait=True)

    On a database like PostgreSQL or Oracle, the above would render a statement like:

        SELECT table.a, table.b FROM table FOR UPDATE NOWAIT

    on other backends, the `nowait` option is ignored and instead would produce:

        SELECT table.a, table.b FROM table FOR UPDATE

    When called with no arguments, the statement will render with the suffix `FOR UPDATE`. Additional arguments can then be provided which allow for common database-specific variants.

    Parameters: | nowait – boolean; will render `FOR UPDATE NOWAIT` on Oracle and PostgreSQL dialects. read – boolean; will render `LOCK IN SHARE MODE` on MySQL, `FOR SHARE` on PostgreSQL. On PostgreSQL, when combined with `nowait`, will render `FOR SHARE NOWAIT`. of – SQL expression or list of SQL expression elements (typically `Column` objects or a compatible expression) which will render into a `FOR UPDATE OF` clause; supported by PostgreSQL and Oracle. May render as a table or as a column depending on backend. skip_locked – boolean, will render `FOR UPDATE SKIP LOCKED` on Oracle and PostgreSQL dialects or `FOR SHARE SKIP LOCKED` if `read=True` is also specified. New in version 1.1.0. key_share – boolean, will render `FOR NO KEY UPDATE`, or if combined with `read=True` will render `FOR KEY SHARE`, on the PostgreSQL dialect. New in version 1.1.0.

class `sqlalchemy.sql.expression.` `CTE`(selectable, name=None, recursive=False, _cte_alias=None, _restates=frozenset(), _suffixes=None)

  Bases: `sqlalchemy.sql.expression.Generative`, `sqlalchemy.sql.expression.HasSuffixes`, `sqlalchemy.sql.expression.Alias`

  Represent a Common Table Expression.

  The `CTE` object is obtained using the `SelectBase.cte()` method from any selectable. See that method for complete examples.

  New in version 0.7.6.

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(name=None, flat=False)

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `description`
    inherited from the `description` attribute of `Alias`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `get_children`(column_collections=True, **kw)
    inherited from the `get_children()` method of `Alias`

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `is_derived_from`(fromclause)
    inherited from the `is_derived_from()` method of `Alias`

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(target=None)
    inherited from the `self_group()` method of `Alias`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `suffix_with`(*expr, **kw)
    inherited from the `suffix_with()` method of `HasSuffixes`

    Add one or more expressions following the statement as a whole.

    This is used to support backend-specific suffix keywords on certain constructs.

    E.g.:

        stmt = select([col1, col2]).cte().suffix_with(
            "cycle empno set y_cycle to 1 default 0", dialect="oracle")

    Multiple suffixes can be specified by multiple calls to `suffix_with()`.

    Parameters: | *expr – textual or `ClauseElement` construct which will be rendered following the target clause. **kw – A single keyword ‘dialect’ is accepted. This is an optional string dialect name which will limit rendering of this suffix to only that dialect.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.` `Executable`

  Bases: `sqlalchemy.sql.expression.Generative`

  Mark a ClauseElement as supporting execution.

  `Executable` is a superclass for all “statement” types of objects, including `select()`, `delete()`, `update()`, `insert()`, `text()`.

  `bind`

    Returns the `Engine` or `Connection` to which this `Executable` is bound, or None if none found.

    This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.

  `execute`(*multiparams, **params)

    Compile and execute this `Executable`.

  `execution_options`(**kw)

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `scalar`(*multiparams, **params)

    Compile and execute this `Executable`, returning the result’s scalar representation.

class `sqlalchemy.sql.expression.` `FromClause`

  Bases: `sqlalchemy.sql.expression.Selectable`

  Represent an element that can be used within the `FROM` clause of a `SELECT` statement.

  The most common forms of `FromClause` are the `Table` and the `select()` constructs. Key features common to all `FromClause` objects include:

  - a `c` collection, which provides per-name access to a collection of `ColumnElement` objects.
  - a `primary_key` attribute, which is a collection of all those `ColumnElement` objects that indicate the `primary_key` flag.
  - Methods to generate various derivations of a “from” clause, including `FromClause.alias()`, `FromClause.join()`, `FromClause.select()`.
  `alias`(name=None, flat=False)

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `c`

    An alias for the `columns` attribute.

  `columns`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `correspond_on_equivalents`(column, equivalents)

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `description`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `foreign_keys`

    Return the collection of ForeignKey objects which this FromClause references.

  `is_derived_from`(fromclause)

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `lateral`(name=None)

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `outerjoin`(right, onclause=None, full=False)

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `primary_key`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `schema` = None

    Define the ‘schema’ attribute for this `FromClause`.

    This is typically `None` for most objects except that of `Table`, where it is taken as the value of the `Table.schema` argument.

  `select`(whereclause=None, **params)

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `tablesample`(sampling, name=None, seed=None)

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

class `sqlalchemy.sql.expression.` `GenerativeSelect`(use_labels=False, for_update=False, limit=None, offset=None, order_by=None, group_by=None, bind=None, autocommit=None)

  Bases: `sqlalchemy.sql.expression.SelectBase`

  Base class for SELECT statements where additional elements can be added.

  This serves as the base for `Select` and `CompoundSelect` where elements such as ORDER BY, GROUP BY can be added and column rendering can be controlled. Compare to `TextAsFrom`, which, while it subclasses `SelectBase` and is also a SELECT construct, represents a fixed textual string which cannot be altered at this level, only wrapped as a subquery.

  New in version 0.9.0: `GenerativeSelect` was added to provide functionality specific to `Select` and `CompoundSelect` while allowing `SelectBase` to be used for other SELECT-like objects, e.g. `TextAsFrom`.

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(name=None, flat=False)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `append_group_by`(*clauses)

    Append the given GROUP BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing GROUP BY criterion.

    This is an in-place mutation method; the `group_by()` method is preferred, as it provides standard method chaining.

  `append_order_by`(*clauses)

    Append the given ORDER BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing ORDER BY criterion.

    This is an in-place mutation method; the `order_by()` method is preferred, as it provides standard method chaining.

  `apply_labels`()

    return a new selectable with the ‘use_labels’ flag set to True.

    This will result in column expressions being generated using labels against their table name, such as “SELECT somecolumn AS tablename_somecolumn”. This allows selectables which contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts among the individual FROM clauses.

  `as_scalar`()
    inherited from the `as_scalar()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, which can be used as a column expression.

    Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.

    The returned object is an instance of `ScalarSelect`.

  `autocommit`()
    inherited from the `autocommit()` method of `SelectBase`

    return a new selectable with the ‘autocommit’ flag set to True.

    Deprecated since version 0.6: `autocommit()` is deprecated. Use `Executable.execution_options()` with the ‘autocommit’ flag.

  `bind`
    inherited from the `bind` attribute of `Executable`

    Returns the `Engine` or `Connection` to which this `Executable` is bound, or None if none found.

    This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `cte`(name=None, recursive=False)
    inherited from the `cte()` method of `HasCTE`

    Return a new `CTE`, or Common Table Expression instance.

    Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.

    CTEs can also be applied to DML constructs UPDATE, INSERT and DELETE on some databases, both as a source of CTE rows when combined with RETURNING, as well as a consumer of CTE rows.

    SQLAlchemy detects `CTE` objects, which are treated similarly to `Alias` objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.

    Changed in version 1.1: Added support for UPDATE/INSERT/DELETE as CTE, CTEs added to UPDATE/INSERT/DELETE.

    Parameters: | name – name given to the common table expression. Like `_FromClause.alias()`, the name can be left as `None` in which case an anonymous symbol will be used at query compile time. recursive – if `True`, will render `WITH RECURSIVE`. A recursive common table expression is intended to be used in conjunction with UNION ALL in order to derive rows from those already selected.

    The following examples include two from PostgreSQL’s documentation at http://www.postgresql.org/docs/current/static/queries-with.html, as well as additional examples.

    Example 1, non recursive:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        orders = Table('orders', metadata,
            Column('region', String),
            Column('amount', Integer),
            Column('product', String),
            Column('quantity', Integer)
        )

        regional_sales = select([
                            orders.c.region,
                            func.sum(orders.c.amount).label('total_sales')
                        ]).group_by(orders.c.region).cte("regional_sales")

        top_regions = select([regional_sales.c.region]).\
                where(
                    regional_sales.c.total_sales >
                    select([
                        func.sum(regional_sales.c.total_sales)/10
                    ])
                ).cte("top_regions")

        statement = select([
                    orders.c.region,
                    orders.c.product,
                    func.sum(orders.c.quantity).label("product_units"),
                    func.sum(orders.c.amount).label("product_sales")
            ]).where(orders.c.region.in_(
                select([top_regions.c.region])
            )).group_by(orders.c.region, orders.c.product)

        result = conn.execute(statement).fetchall()

    Example 2, WITH RECURSIVE:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        parts = Table('parts', metadata,
            Column('part', String),
            Column('sub_part', String),
            Column('quantity', Integer),
        )

        included_parts = select([
                            parts.c.sub_part,
                            parts.c.part,
                            parts.c.quantity]).\
                            where(parts.c.part=='our part').\
                            cte(recursive=True)

        incl_alias = included_parts.alias()
        parts_alias = parts.alias()
        included_parts = included_parts.union_all(
            select([
                parts_alias.c.sub_part,
                parts_alias.c.part,
                parts_alias.c.quantity
            ]).
                where(parts_alias.c.part==incl_alias.c.sub_part)
        )

        statement = select([
                    included_parts.c.sub_part,
                    func.sum(included_parts.c.quantity).
                      label('total_quantity')
                ]).\
                group_by(included_parts.c.sub_part)

        result = conn.execute(statement).fetchall()

    Example 3, an upsert using UPDATE and INSERT with CTEs:

        from datetime import date
        from sqlalchemy import (MetaData, Table, Column, Integer,
                                Date, select, literal, and_, exists)

        metadata = MetaData()

        visitors = Table('visitors', metadata,
            Column('product_id', Integer, primary_key=True),
            Column('date', Date, primary_key=True),
            Column('count', Integer),
        )

        # add 5 visitors for the product_id == 1
        product_id = 1
        day = date.today()
        count = 5

        update_cte = (
            visitors.update()
            .where(and_(visitors.c.product_id == product_id,
                        visitors.c.date == day))
            .values(count=visitors.c.count + count)
            .returning(literal(1))
            .cte('update_cte')
        )

        upsert = visitors.insert().from_select(
            [visitors.c.product_id, visitors.c.date, visitors.c.count],
            select([literal(product_id), literal(day), literal(count)])
                .where(~exists(update_cte.select()))
        )

        connection.execute(upsert)

    See also

    `orm.query.Query.cte()` - ORM version of `HasCTE.cte()`.

  `description`
    inherited from the `description` attribute of `FromClause`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `execute`(*multiparams, **params)
    inherited from the `execute()` method of `Executable`

    Compile and execute this `Executable`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `for_update`

    Provide legacy dialect support for the `for_update` attribute.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `get_children`(**kwargs)
    inherited from the `get_children()` method of `ClauseElement`

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `group_by`(*clauses)

    return a new selectable with the given list of GROUP BY criterion applied.

    The criterion will be appended to any pre-existing GROUP BY criterion.

  `is_derived_from`(fromclause)
    inherited from the `is_derived_from()` method of `FromClause`

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `label`(name)
    inherited from the `label()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.

    See also

    `as_scalar()`.

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `limit`(limit)

    return a new selectable with the given LIMIT criterion applied.

    This is a numerical value which usually renders as a `LIMIT` expression in the resulting select. Backends that don’t support `LIMIT` will attempt to provide similar functionality.

    Changed in version 1.0.0: - `Select.limit()` can now accept arbitrary SQL expressions as well as integer values.

    Parameters: | limit – an integer LIMIT parameter, or a SQL expression that provides an integer result.

  `offset`(offset)

    return a new selectable with the given OFFSET criterion applied.

    This is a numeric value which usually renders as an `OFFSET` expression in the resulting select. Backends that don’t support `OFFSET` will attempt to provide similar functionality.

    Changed in version 1.0.0: - `Select.offset()` can now accept arbitrary SQL expressions as well as integer values.

    Parameters: | offset – an integer OFFSET parameter, or a SQL expression that provides an integer result.

  `order_by`(*clauses)

    return a new selectable with the given list of ORDER BY criterion applied.

    The criterion will be appended to any pre-existing ORDER BY criterion.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `scalar`(*multiparams, **params)
    inherited from the `scalar()` method of `Executable`

    Compile and execute this `Executable`, returning the result’s scalar representation.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

  `with_for_update`(nowait=False, read=False, of=None, skip_locked=False, key_share=False)

    Specify a `FOR UPDATE` clause for this `GenerativeSelect`.

    E.g.:

        stmt = select([table]).with_for_update(nowait=True)

    On a database like PostgreSQL or Oracle, the above would render a statement like:

        SELECT table.a, table.b FROM table FOR UPDATE NOWAIT

    on other backends, the `nowait` option is ignored and instead would produce:

        SELECT table.a, table.b FROM table FOR UPDATE

    When called with no arguments, the statement will render with the suffix `FOR UPDATE`. Additional arguments can then be provided which allow for common database-specific variants.

    Parameters: | nowait – boolean; will render `FOR UPDATE NOWAIT` on Oracle and PostgreSQL dialects. read – boolean; will render `LOCK IN SHARE MODE` on MySQL, `FOR SHARE` on PostgreSQL. On PostgreSQL, when combined with `nowait`, will render `FOR SHARE NOWAIT`. of – SQL expression or list of SQL expression elements (typically `Column` objects or a compatible expression) which will render into a `FOR UPDATE OF` clause; supported by PostgreSQL and Oracle. May render as a table or as a column depending on backend. skip_locked – boolean, will render `FOR UPDATE SKIP LOCKED` on Oracle and PostgreSQL dialects or `FOR SHARE SKIP LOCKED` if `read=True` is also specified. New in version 1.1.0. key_share – boolean, will render `FOR NO KEY UPDATE`, or if combined with `read=True` will render `FOR KEY SHARE`, on the PostgreSQL dialect. New in version 1.1.0.

class `sqlalchemy.sql.expression.` `HasCTE`

  Mixin that declares a class to include CTE support.

  New in version 1.1.

  `cte`(name=None, recursive=False)

    Return a new `CTE`, or Common Table Expression instance.

    Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.

    CTEs can also be applied to DML constructs UPDATE, INSERT and DELETE on some databases, both as a source of CTE rows when combined with RETURNING, as well as a consumer of CTE rows.

    SQLAlchemy detects `CTE` objects, which are treated similarly to `Alias` objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.

    Changed in version 1.1: Added support for UPDATE/INSERT/DELETE as CTE, CTEs added to UPDATE/INSERT/DELETE.

    Parameters: | name – name given to the common table expression. Like `_FromClause.alias()`, the name can be left as `None` in which case an anonymous symbol will be used at query compile time. recursive – if `True`, will render `WITH RECURSIVE`. A recursive common table expression is intended to be used in conjunction with UNION ALL in order to derive rows from those already selected.

    The following examples include two from PostgreSQL’s documentation at http://www.postgresql.org/docs/current/static/queries-with.html, as well as additional examples.

    Example 1, non recursive:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        orders = Table('orders', metadata,
            Column('region', String),
            Column('amount', Integer),
            Column('product', String),
            Column('quantity', Integer)
        )

        regional_sales = select([
                            orders.c.region,
                            func.sum(orders.c.amount).label('total_sales')
                        ]).group_by(orders.c.region).cte("regional_sales")

        top_regions = select([regional_sales.c.region]).\
                where(
                    regional_sales.c.total_sales >
                    select([
                        func.sum(regional_sales.c.total_sales)/10
                    ])
                ).cte("top_regions")

        statement = select([
                    orders.c.region,
                    orders.c.product,
                    func.sum(orders.c.quantity).label("product_units"),
                    func.sum(orders.c.amount).label("product_sales")
            ]).where(orders.c.region.in_(
                select([top_regions.c.region])
            )).group_by(orders.c.region, orders.c.product)

        result = conn.execute(statement).fetchall()

    Example 2, WITH RECURSIVE:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        parts = Table('parts', metadata,
            Column('part', String),
            Column('sub_part', String),
            Column('quantity', Integer),
        )

        included_parts = select([
                            parts.c.sub_part,
                            parts.c.part,
                            parts.c.quantity]).\
                            where(parts.c.part=='our part').\
                            cte(recursive=True)

        incl_alias = included_parts.alias()
        parts_alias = parts.alias()
        included_parts = included_parts.union_all(
            select([
                parts_alias.c.sub_part,
                parts_alias.c.part,
                parts_alias.c.quantity
            ]).
                where(parts_alias.c.part==incl_alias.c.sub_part)
        )

        statement = select([
                    included_parts.c.sub_part,
                    func.sum(included_parts.c.quantity).
                      label('total_quantity')
                ]).\
                group_by(included_parts.c.sub_part)

        result = conn.execute(statement).fetchall()

    Example 3, an upsert using UPDATE and INSERT with CTEs:

        from datetime import date
        from sqlalchemy import (MetaData, Table, Column, Integer,
                                Date, select, literal, and_, exists)

        metadata = MetaData()

        visitors = Table('visitors', metadata,
            Column('product_id', Integer, primary_key=True),
            Column('date', Date, primary_key=True),
            Column('count', Integer),
        )

        # add 5 visitors for the product_id == 1
        product_id = 1
        day = date.today()
        count = 5

        update_cte = (
            visitors.update()
            .where(and_(visitors.c.product_id == product_id,
                        visitors.c.date == day))
            .values(count=visitors.c.count + count)
            .returning(literal(1))
            .cte('update_cte')
        )

        upsert = visitors.insert().from_select(
            [visitors.c.product_id, visitors.c.date, visitors.c.count],
            select([literal(product_id), literal(day), literal(count)])
                .where(~exists(update_cte.select()))
        )

        connection.execute(upsert)

    See also

    `orm.query.Query.cte()` - ORM version of `HasCTE.cte()`.

class `sqlalchemy.sql.expression.` `HasPrefixes`
  `prefix_with`(*expr, **kw)

    Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.

    This is used to support backend-specific prefix keywords such as those provided by MySQL.

    E.g.:

        stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")

    Multiple prefixes can be specified by multiple calls to `prefix_with()`.

    Parameters: | *expr – textual or `ClauseElement` construct which will be rendered following the INSERT, UPDATE, or DELETE keyword. **kw – A single keyword ‘dialect’ is accepted. This is an optional string dialect name which will limit rendering of this prefix to only that dialect.

class `sqlalchemy.sql.expression.` `HasSuffixes`
  `suffix_with`(*expr, **kw)

    Add one or more expressions following the statement as a whole.

    This is used to support backend-specific suffix keywords on certain constructs.

    E.g.:

        stmt = select([col1, col2]).cte().suffix_with(
            "cycle empno set y_cycle to 1 default 0", dialect="oracle")

    Multiple suffixes can be specified by multiple calls to `suffix_with()`.

    Parameters: | *expr – textual or `ClauseElement` construct which will be rendered following the target clause. **kw – A single keyword ‘dialect’ is accepted. This is an optional string dialect name which will limit rendering of this suffix to only that dialect.

class `sqlalchemy.sql.expression.` `Join`(left, right, onclause=None, isouter=False, full=False)

  Bases: `sqlalchemy.sql.expression.FromClause`

  represent a `JOIN` construct between two `FromClause` elements.

  The public constructor function for `Join` is the module-level `join()` function, as well as the `FromClause.join()` method of any `FromClause` (e.g. such as `Table`).

  See also

  `join()`

  `FromClause.join()`

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__init__`(left, right, onclause=None, isouter=False, full=False)

    Construct a new `Join`.

    The usual entrypoint here is the `join()` function or the `FromClause.join()` method of any `FromClause` object.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(sqlutil, name=None, flat=False)

    return an alias of this `Join`.

    The default behavior here is to first produce a SELECT construct from this `Join`, then to produce an `Alias` from that. So given a join of the form:

        j = table_a.join(table_b, table_a.c.id == table_b.c.a_id)

    The JOIN by itself would look like:

        table_a JOIN table_b ON table_a.id = table_b.a_id

    Whereas the alias of the above, `j.alias()`, would in a SELECT context look like:

        (SELECT table_a.id AS table_a_id, table_b.id AS table_b_id,
            table_b.a_id AS table_b_a_id
            FROM table_a
            JOIN table_b ON table_a.id = table_b.a_id) AS anon_1

    The equivalent long-hand form, given a `Join` object `j`, is:

        from sqlalchemy import select, alias
        j = alias(
            select([j.left, j.right]).\
                select_from(j).\
                with_labels(True).\
                correlate(False),
            name=name
        )

    The selectable produced by `Join.alias()` features the same columns as that of the two individual selectables presented under a single name - the individual columns are “auto-labeled”, meaning the `.c.` collection of the resulting `Alias` represents the names of the individual columns using a `<tablename>_<columname>` scheme:

        j.c.table_a_id
        j.c.table_b_a_id

    `Join.alias()` also features an alternate option for aliasing joins which produces no enclosing SELECT and does not normally apply labels to the column names. The `flat=True` option will call `FromClause.alias()` against the left and right sides individually. Using this option, no new `SELECT` is produced; we instead, from a construct as below:

        j = table_a.join(table_b, table_a.c.id == table_b.c.a_id)
        j = j.alias(flat=True)

    we get a result like this:

        table_a AS table_a_1 JOIN table_b AS table_b_1 ON
        table_a_1.id = table_b_1.a_id

    The `flat=True` argument is also propagated to the contained selectables, so that a composite join such as:

        j = table_a.join(
                table_b.join(table_c,
                        table_b.c.id == table_c.c.b_id),
                table_b.c.a_id == table_a.c.id
            ).alias(flat=True)

    Will produce an expression like:

        table_a AS table_a_1 JOIN (
                table_b AS table_b_1 JOIN table_c AS table_c_1
                ON table_b_1.id = table_c_1.b_id
        ) ON table_a_1.id = table_b_1.a_id

    The standalone `alias()` function as well as the base `FromClause.alias()` method also support the `flat=True` argument as a no-op, so that the argument can be passed to the `alias()` method of any selectable.

    New in version 0.9.0: Added the `flat=True` option to create “aliases” of joins without enclosing inside of a SELECT subquery.

    Parameters: | name – name given to the alias. flat – if True, produce an alias of the left and right sides of this `Join` and return the join of those two selectables. This produces join expression that does not include an enclosing SELECT. New in version 0.9.0.

    See also

    `alias()`

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `description`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `get_children`(**kwargs)

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `is_derived_from`(fromclause)

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **kwargs)

    Create a `Select` from this `Join`.

    The equivalent long-hand form, given a `Join` object `j`, is:

        from sqlalchemy import select
        j = select([j.left, j.right], **kw).\
                    where(whereclause).\
                    select_from(j)

    Parameters: | whereclause – the WHERE criterion that will be sent to the `select()` function **kwargs – all other kwargs are sent to the underlying `select()` function.

  `self_group`(against=None)

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.` `Lateral`(selectable, name=None)

  Bases: `sqlalchemy.sql.expression.Alias`

  Represent a LATERAL subquery.

  This object is constructed from the `lateral()` module level function as well as the `FromClause.lateral()` method available on all `FromClause` subclasses.

  While LATERAL is part of the SQL standard, curently only more recent PostgreSQL versions provide support for this keyword.

  New in version 1.1.

  See also

  LATERAL correlation - overview of usage.

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(name=None, flat=False)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `description`
    inherited from the `description` attribute of `Alias`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `get_children`(column_collections=True, **kw)
    inherited from the `get_children()` method of `Alias`

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `is_derived_from`(fromclause)
    inherited from the `is_derived_from()` method of `Alias`

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(target=None)
    inherited from the `self_group()` method of `Alias`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.` `ScalarSelect`(element)

  Bases: `sqlalchemy.sql.expression.Generative`, `sqlalchemy.sql.expression.Grouping`

  `self_group`(**kwargs)

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `where`(crit)

    Apply a WHERE clause to the SELECT statement referred to by this `ScalarSelect`.

class `sqlalchemy.sql.expression.` `Select`(columns=None, whereclause=None, from_obj=None, distinct=False, having=None, correlate=True, prefixes=None, suffixes=None, **kwargs)

  Bases: `sqlalchemy.sql.expression.HasPrefixes`, `sqlalchemy.sql.expression.HasSuffixes`, `sqlalchemy.sql.expression.GenerativeSelect`

  Represents a `SELECT` statement.

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__init__`(columns=None, whereclause=None, from_obj=None, distinct=False, having=None, correlate=True, prefixes=None, suffixes=None, **kwargs)

    Construct a new `Select` object.

    This constructor is mirrored as a public API function; see `select()` for a full usage and argument description.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(name=None, flat=False)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `append_column`(column)

    append the given column expression to the columns clause of this select() construct.

    E.g.:

        my_select.append_column(some_table.c.new_column)

    This is an in-place mutation method; the `column()` method is preferred, as it provides standard method chaining.

    See the documentation for `Select.with_only_columns()` for guidelines on adding /replacing the columns of a `Select` object.

  `append_correlation`(fromclause)

    append the given correlation expression to this select() construct.

    This is an in-place mutation method; the `correlate()` method is preferred, as it provides standard method chaining.

  `append_from`(fromclause)

    append the given FromClause expression to this select() construct’s FROM clause.

    This is an in-place mutation method; the `select_from()` method is preferred, as it provides standard method chaining.

  `append_group_by`(*clauses)
    inherited from the `append_group_by()` method of `GenerativeSelect`

    Append the given GROUP BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing GROUP BY criterion.

    This is an in-place mutation method; the `group_by()` method is preferred, as it provides standard method chaining.

  `append_having`(having)

    append the given expression to this select() construct’s HAVING criterion.

    The expression will be joined to existing HAVING criterion via AND.

    This is an in-place mutation method; the `having()` method is preferred, as it provides standard method chaining.

  `append_order_by`(*clauses)
    inherited from the `append_order_by()` method of `GenerativeSelect`

    Append the given ORDER BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing ORDER BY criterion.

    This is an in-place mutation method; the `order_by()` method is preferred, as it provides standard method chaining.

  `append_prefix`(clause)

    append the given columns clause prefix expression to this select() construct.

    This is an in-place mutation method; the `prefix_with()` method is preferred, as it provides standard method chaining.

  `append_whereclause`(whereclause)

    append the given expression to this select() construct’s WHERE criterion.

    The expression will be joined to existing WHERE criterion via AND.

    This is an in-place mutation method; the `where()` method is preferred, as it provides standard method chaining.

  `apply_labels`()
    inherited from the `apply_labels()` method of `GenerativeSelect`

    return a new selectable with the ‘use_labels’ flag set to True.

    This will result in column expressions being generated using labels against their table name, such as “SELECT somecolumn AS tablename_somecolumn”. This allows selectables which contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts among the individual FROM clauses.

  `as_scalar`()
    inherited from the `as_scalar()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, which can be used as a column expression.

    Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.

    The returned object is an instance of `ScalarSelect`.

  `autocommit`()
    inherited from the `autocommit()` method of `SelectBase`

    return a new selectable with the ‘autocommit’ flag set to True.

    Deprecated since version 0.6: `autocommit()` is deprecated. Use `Executable.execution_options()` with the ‘autocommit’ flag.

  `bind`

    Returns the `Engine` or `Connection` to which this `Executable` is bound, or None if none found.

    This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `column`(column)

    return a new select() construct with the given column expression added to its columns clause.

    E.g.:

        my_select = my_select.column(table.c.new_column)

    See the documentation for `Select.with_only_columns()` for guidelines on adding /replacing the columns of a `Select` object.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correlate`(*fromclauses)

    return a new `Select` which will correlate the given FROM clauses to that of an enclosing `Select`.

    Calling this method turns off the `Select` object’s default behavior of “auto-correlation”. Normally, FROM elements which appear in a `Select` that encloses this one via its WHERE clause, ORDER BY, HAVING or columns clause will be omitted from this `Select` object’s FROM clause. Setting an explicit correlation collection using the `Select.correlate()` method provides a fixed list of FROM objects that can potentially take place in this process.

    When `Select.correlate()` is used to apply specific FROM clauses for correlation, the FROM elements become candidates for correlation regardless of how deeply nested this `Select` object is, relative to an enclosing `Select` which refers to the same FROM object. This is in contrast to the behavior of “auto-correlation” which only correlates to an immediate enclosing `Select`. Multi-level correlation ensures that the link between enclosed and enclosing `Select` is always via at least one WHERE/ORDER BY/HAVING/columns clause in order for correlation to take place.

    If `None` is passed, the `Select` object will correlate none of its FROM entries, and all will render unconditionally in the local FROM clause.

    Parameters: | *fromclauses – a list of one or more `FromClause` constructs, or other compatible constructs (i.e. ORM-mapped classes) to become part of the correlate collection. Changed in version 0.8.0: ORM-mapped classes are accepted by `Select.correlate()`.

    Changed in version 0.8.0: The `Select.correlate()` method no longer unconditionally removes entries from the FROM clause; instead, the candidate FROM entries must also be matched by a FROM entry located in an enclosing `Select`, which ultimately encloses this one as present in the WHERE clause, ORDER BY clause, HAVING clause, or columns clause of an enclosing `Select()`.

    Changed in version 0.8.2: explicit correlation takes place via any level of nesting of `Select` objects; in previous 0.8 versions, correlation would only occur relative to the immediate enclosing `Select` construct.

    See also

    `Select.correlate_except()`

    Correlated Subqueries

  `correlate_except`(*fromclauses)

    return a new `Select` which will omit the given FROM clauses from the auto-correlation process.

    Calling `Select.correlate_except()` turns off the `Select` object’s default behavior of “auto-correlation” for the given FROM elements. An element specified here will unconditionally appear in the FROM list, while all other FROM elements remain subject to normal auto-correlation behaviors.

    Changed in version 0.8.2: The `Select.correlate_except()` method was improved to fully prevent FROM clauses specified here from being omitted from the immediate FROM clause of this `Select`.

    If `None` is passed, the `Select` object will correlate all of its FROM entries.

    Changed in version 0.8.2: calling `correlate_except(None)` will correctly auto-correlate all FROM clauses.

    Parameters: | *fromclauses – a list of one or more `FromClause` constructs, or other compatible constructs (i.e. ORM-mapped classes) to become part of the correlate-exception collection.

    See also

    `Select.correlate()`

    Correlated Subqueries

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `cte`(name=None, recursive=False)
    inherited from the `cte()` method of `HasCTE`

    Return a new `CTE`, or Common Table Expression instance.

    Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.

    CTEs can also be applied to DML constructs UPDATE, INSERT and DELETE on some databases, both as a source of CTE rows when combined with RETURNING, as well as a consumer of CTE rows.

    SQLAlchemy detects `CTE` objects, which are treated similarly to `Alias` objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.

    Changed in version 1.1: Added support for UPDATE/INSERT/DELETE as CTE, CTEs added to UPDATE/INSERT/DELETE.

    Parameters: | name – name given to the common table expression. Like `_FromClause.alias()`, the name can be left as `None` in which case an anonymous symbol will be used at query compile time. recursive – if `True`, will render `WITH RECURSIVE`. A recursive common table expression is intended to be used in conjunction with UNION ALL in order to derive rows from those already selected.

    The following examples include two from PostgreSQL’s documentation at http://www.postgresql.org/docs/current/static/queries-with.html, as well as additional examples.

    Example 1, non recursive:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        orders = Table('orders', metadata,
            Column('region', String),
            Column('amount', Integer),
            Column('product', String),
            Column('quantity', Integer)
        )

        regional_sales = select([
                            orders.c.region,
                            func.sum(orders.c.amount).label('total_sales')
                        ]).group_by(orders.c.region).cte("regional_sales")

        top_regions = select([regional_sales.c.region]).\
                where(
                    regional_sales.c.total_sales >
                    select([
                        func.sum(regional_sales.c.total_sales)/10
                    ])
                ).cte("top_regions")

        statement = select([
                    orders.c.region,
                    orders.c.product,
                    func.sum(orders.c.quantity).label("product_units"),
                    func.sum(orders.c.amount).label("product_sales")
            ]).where(orders.c.region.in_(
                select([top_regions.c.region])
            )).group_by(orders.c.region, orders.c.product)

        result = conn.execute(statement).fetchall()

    Example 2, WITH RECURSIVE:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        parts = Table('parts', metadata,
            Column('part', String),
            Column('sub_part', String),
            Column('quantity', Integer),
        )

        included_parts = select([
                            parts.c.sub_part,
                            parts.c.part,
                            parts.c.quantity]).\
                            where(parts.c.part=='our part').\
                            cte(recursive=True)

        incl_alias = included_parts.alias()
        parts_alias = parts.alias()
        included_parts = included_parts.union_all(
            select([
                parts_alias.c.sub_part,
                parts_alias.c.part,
                parts_alias.c.quantity
            ]).
                where(parts_alias.c.part==incl_alias.c.sub_part)
        )

        statement = select([
                    included_parts.c.sub_part,
                    func.sum(included_parts.c.quantity).
                      label('total_quantity')
                ]).\
                group_by(included_parts.c.sub_part)

        result = conn.execute(statement).fetchall()

    Example 3, an upsert using UPDATE and INSERT with CTEs:

        from datetime import date
        from sqlalchemy import (MetaData, Table, Column, Integer,
                                Date, select, literal, and_, exists)

        metadata = MetaData()

        visitors = Table('visitors', metadata,
            Column('product_id', Integer, primary_key=True),
            Column('date', Date, primary_key=True),
            Column('count', Integer),
        )

        # add 5 visitors for the product_id == 1
        product_id = 1
        day = date.today()
        count = 5

        update_cte = (
            visitors.update()
            .where(and_(visitors.c.product_id == product_id,
                        visitors.c.date == day))
            .values(count=visitors.c.count + count)
            .returning(literal(1))
            .cte('update_cte')
        )

        upsert = visitors.insert().from_select(
            [visitors.c.product_id, visitors.c.date, visitors.c.count],
            select([literal(product_id), literal(day), literal(count)])
                .where(~exists(update_cte.select()))
        )

        connection.execute(upsert)

    See also

    `orm.query.Query.cte()` - ORM version of `HasCTE.cte()`.

  `description`
    inherited from the `description` attribute of `FromClause`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `distinct`(*expr)

    Return a new select() construct which will apply DISTINCT to its columns clause.

    Parameters: | *expr – optional column expressions. When present, the PostgreSQL dialect will render a `DISTINCT ON (<expressions>>)` construct.

  `except_`(other, **kwargs)

    return a SQL EXCEPT of this select() construct against the given selectable.

  `except_all`(other, **kwargs)

    return a SQL EXCEPT ALL of this select() construct against the given selectable.

  `execute`(*multiparams, **params)
    inherited from the `execute()` method of `Executable`

    Compile and execute this `Executable`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `for_update`
    inherited from the `for_update` attribute of `GenerativeSelect`

    Provide legacy dialect support for the `for_update` attribute.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `froms`

    Return the displayed list of FromClause elements.

  `get_children`(column_collections=True, **kwargs)

    return child elements as per the ClauseElement specification.

  `group_by`(*clauses)
    inherited from the `group_by()` method of `GenerativeSelect`

    return a new selectable with the given list of GROUP BY criterion applied.

    The criterion will be appended to any pre-existing GROUP BY criterion.

  `having`(having)

    return a new select() construct with the given expression added to its HAVING clause, joined to the existing clause via AND, if any.

  `inner_columns`

    an iterator of all ColumnElement expressions which would be rendered into the columns clause of the resulting SELECT statement.

  `intersect`(other, **kwargs)

    return a SQL INTERSECT of this select() construct against the given selectable.

  `intersect_all`(other, **kwargs)

    return a SQL INTERSECT ALL of this select() construct against the given selectable.

  `is_derived_from`(fromclause)

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `label`(name)
    inherited from the `label()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.

    See also

    `as_scalar()`.

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `limit`(limit)
    inherited from the `limit()` method of `GenerativeSelect`

    return a new selectable with the given LIMIT criterion applied.

    This is a numerical value which usually renders as a `LIMIT` expression in the resulting select. Backends that don’t support `LIMIT` will attempt to provide similar functionality.

    Changed in version 1.0.0: - `Select.limit()` can now accept arbitrary SQL expressions as well as integer values.

    Parameters: | limit – an integer LIMIT parameter, or a SQL expression that provides an integer result.

  `locate_all_froms`()

    return a Set of all FromClause elements referenced by this Select.

    This set is a superset of that returned by the `froms` property, which is specifically for those FromClause elements that would actually be rendered.

  `offset`(offset)
    inherited from the `offset()` method of `GenerativeSelect`

    return a new selectable with the given OFFSET criterion applied.

    This is a numeric value which usually renders as an `OFFSET` expression in the resulting select. Backends that don’t support `OFFSET` will attempt to provide similar functionality.

    Changed in version 1.0.0: - `Select.offset()` can now accept arbitrary SQL expressions as well as integer values.

    Parameters: | offset – an integer OFFSET parameter, or a SQL expression that provides an integer result.

  `order_by`(*clauses)
    inherited from the `order_by()` method of `GenerativeSelect`

    return a new selectable with the given list of ORDER BY criterion applied.

    The criterion will be appended to any pre-existing ORDER BY criterion.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `prefix_with`(*expr, **kw)
    inherited from the `prefix_with()` method of `HasPrefixes`

    Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.

    This is used to support backend-specific prefix keywords such as those provided by MySQL.

    E.g.:

        stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")

    Multiple prefixes can be specified by multiple calls to `prefix_with()`.

    Parameters: | *expr – textual or `ClauseElement` construct which will be rendered following the INSERT, UPDATE, or DELETE keyword. **kw – A single keyword ‘dialect’ is accepted. This is an optional string dialect name which will limit rendering of this prefix to only that dialect.

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `reduce_columns`(sqlutil, only_synonyms=True)

    Return a new :func`.select` construct with redundantly named, equivalently-valued columns removed from the columns clause.

    “Redundant” here means two columns where one refers to the other either based on foreign key, or via a simple equality comparison in the WHERE clause of the statement. The primary purpose of this method is to automatically construct a select statement with all uniquely-named columns, without the need to use table-qualified labels as `apply_labels()` does.

    When columns are omitted based on foreign key, the referred-to column is the one that’s kept. When columns are omitted based on WHERE eqivalence, the first column in the columns clause is the one that’s kept.

    Parameters: | only_synonyms – when True, limit the removal of columns to those which have the same name as the equivalent. Otherwise, all columns that are equivalent to another are removed.

    New in version 0.8.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `scalar`(*multiparams, **params)
    inherited from the `scalar()` method of `Executable`

    Compile and execute this `Executable`, returning the result’s scalar representation.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `select_from`(fromclause)

    return a new `select()` construct with the given FROM expression merged into its list of FROM objects.

    E.g.:

        table1 = table('t1', column('a'))
        table2 = table('t2', column('b'))
        s = select([table1.c.a]).\
            select_from(
                table1.join(table2, table1.c.a==table2.c.b)
            )

    The “from” list is a unique set on the identity of each element, so adding an already present `Table` or other selectable will have no effect. Passing a `Join` that refers to an already present `Table` or other selectable will have the effect of concealing the presence of that selectable as an individual element in the rendered FROM list, instead rendering it into a JOIN clause.

    While the typical purpose of `Select.select_from()` is to replace the default, derived FROM clause with a join, it can also be called with individual table elements, multiple times if desired, in the case that the FROM clause cannot be fully derived from the columns clause:

        select([func.count('*')]).select_from(table1)

  `self_group`(against=None)

    return a ‘grouping’ construct as per the ClauseElement specification.

    This produces an element that can be embedded in an expression. Note that this method is called automatically as needed when constructing expressions and should not require explicit use.

  `suffix_with`(*expr, **kw)
    inherited from the `suffix_with()` method of `HasSuffixes`

    Add one or more expressions following the statement as a whole.

    This is used to support backend-specific suffix keywords on certain constructs.

    E.g.:

        stmt = select([col1, col2]).cte().suffix_with(
            "cycle empno set y_cycle to 1 default 0", dialect="oracle")

    Multiple suffixes can be specified by multiple calls to `suffix_with()`.

    Parameters: | *expr – textual or `ClauseElement` construct which will be rendered following the target clause. **kw – A single keyword ‘dialect’ is accepted. This is an optional string dialect name which will limit rendering of this suffix to only that dialect.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `union`(other, **kwargs)

    return a SQL UNION of this select() construct against the given selectable.

  `union_all`(other, **kwargs)

    return a SQL UNION ALL of this select() construct against the given selectable.

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

  `where`(whereclause)

    return a new select() construct with the given expression added to its WHERE clause, joined to the existing clause via AND, if any.

  `with_for_update`(nowait=False, read=False, of=None, skip_locked=False, key_share=False)
    inherited from the `with_for_update()` method of `GenerativeSelect`

    Specify a `FOR UPDATE` clause for this `GenerativeSelect`.

    E.g.:

        stmt = select([table]).with_for_update(nowait=True)

    On a database like PostgreSQL or Oracle, the above would render a statement like:

        SELECT table.a, table.b FROM table FOR UPDATE NOWAIT

    on other backends, the `nowait` option is ignored and instead would produce:

        SELECT table.a, table.b FROM table FOR UPDATE

    When called with no arguments, the statement will render with the suffix `FOR UPDATE`. Additional arguments can then be provided which allow for common database-specific variants.

    Parameters: | nowait – boolean; will render `FOR UPDATE NOWAIT` on Oracle and PostgreSQL dialects. read – boolean; will render `LOCK IN SHARE MODE` on MySQL, `FOR SHARE` on PostgreSQL. On PostgreSQL, when combined with `nowait`, will render `FOR SHARE NOWAIT`. of – SQL expression or list of SQL expression elements (typically `Column` objects or a compatible expression) which will render into a `FOR UPDATE OF` clause; supported by PostgreSQL and Oracle. May render as a table or as a column depending on backend. skip_locked – boolean, will render `FOR UPDATE SKIP LOCKED` on Oracle and PostgreSQL dialects or `FOR SHARE SKIP LOCKED` if `read=True` is also specified. New in version 1.1.0. key_share – boolean, will render `FOR NO KEY UPDATE`, or if combined with `read=True` will render `FOR KEY SHARE`, on the PostgreSQL dialect. New in version 1.1.0.

  `with_hint`(selectable, text, dialect_name='*')

    Add an indexing or other executional context hint for the given selectable to this `Select`.

    The text of the hint is rendered in the appropriate location for the database backend in use, relative to the given `Table` or `Alias` passed as the `selectable` argument. The dialect implementation typically uses Python string substitution syntax with the token `%(name)s` to render the name of the table or alias. E.g. when using Oracle, the following:

        select([mytable]).\
            with_hint(mytable, "index(%(name)s ix_mytable)")

    Would render SQL as:

        select /*+ index(mytable ix_mytable) */ ... from mytable

    The `dialect_name` option will limit the rendering of a particular hint to a particular backend. Such as, to add hints for both Oracle and Sybase simultaneously:

        select([mytable]).\
            with_hint(mytable, "index(%(name)s ix_mytable)", 'oracle').\
            with_hint(mytable, "WITH INDEX ix_mytable", 'sybase')

    See also

    `Select.with_statement_hint()`

  `with_only_columns`(columns)

    Return a new `select()` construct with its columns clause replaced with the given columns.

    This method is exactly equivalent to as if the original `select()` had been called with the given columns clause. I.e. a statement:

        s = select([table1.c.a, table1.c.b])
        s = s.with_only_columns([table1.c.b])

    should be exactly equivalent to:

        s = select([table1.c.b])

    This means that FROM clauses which are only derived from the column list will be discarded if the new column list no longer contains that FROM:

        >>> table1 = table('t1', column('a'), column('b'))
        >>> table2 = table('t2', column('a'), column('b'))
        >>> s1 = select([table1.c.a, table2.c.b])
        >>> print s1
        SELECT t1.a, t2.b FROM t1, t2
        >>> s2 = s1.with_only_columns([table2.c.b])
        >>> print s2
        SELECT t2.b FROM t1

    The preferred way to maintain a specific FROM clause in the construct, assuming it won’t be represented anywhere else (i.e. not in the WHERE clause, etc.) is to set it using `Select.select_from()`:

        >>> s1 = select([table1.c.a, table2.c.b]).\
        ...         select_from(table1.join(table2,
        ...                 table1.c.a==table2.c.a))
        >>> s2 = s1.with_only_columns([table2.c.b])
        >>> print s2
        SELECT t2.b FROM t1 JOIN t2 ON t1.a=t2.a

    Care should also be taken to use the correct set of column objects passed to `Select.with_only_columns()`. Since the method is essentially equivalent to calling the `select()` construct in the first place with the given columns, the columns passed to `Select.with_only_columns()` should usually be a subset of those which were passed to the `select()` construct, not those which are available from the `.c` collection of that `select()`. That is:

        s = select([table1.c.a, table1.c.b]).select_from(table1)
        s = s.with_only_columns([table1.c.b])

    and not:

        # usually incorrect
        s = s.with_only_columns([s.c.b])

    The latter would produce the SQL:

        SELECT b
        FROM (SELECT t1.a AS a, t1.b AS b
        FROM t1), t1

    Since the `select()` construct is essentially being asked to select both from `table1` as well as itself.

  `with_statement_hint`(text, dialect_name='*')

    add a statement hint to this `Select`.

    This method is similar to `Select.with_hint()` except that it does not require an individual table, and instead applies to the statement as a whole.

    Hints here are specific to the backend database and may include directives such as isolation levels, file directives, fetch directives, etc.

    New in version 1.0.0.

    See also

    `Select.with_hint()`

class `sqlalchemy.sql.expression.` `Selectable`

  Bases: `sqlalchemy.sql.expression.ClauseElement`

  mark a class as being selectable

class `sqlalchemy.sql.expression.` `SelectBase`

  Bases: `sqlalchemy.sql.expression.HasCTE`, `sqlalchemy.sql.expression.Executable`, `sqlalchemy.sql.expression.FromClause`

  Base class for SELECT statements.

  This includes `Select`, `CompoundSelect` and `TextAsFrom`.

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__init__`
    inherited from the `__init__` attribute of `object`

    Initialize self. See help(type(self)) for accurate signature.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(name=None, flat=False)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `as_scalar`()

    return a ‘scalar’ representation of this selectable, which can be used as a column expression.

    Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.

    The returned object is an instance of `ScalarSelect`.

  `autocommit`()

    return a new selectable with the ‘autocommit’ flag set to True.

    Deprecated since version 0.6: `autocommit()` is deprecated. Use `Executable.execution_options()` with the ‘autocommit’ flag.

  `bind`
    inherited from the `bind` attribute of `Executable`

    Returns the `Engine` or `Connection` to which this `Executable` is bound, or None if none found.

    This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `cte`(name=None, recursive=False)
    inherited from the `cte()` method of `HasCTE`

    Return a new `CTE`, or Common Table Expression instance.

    Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.

    CTEs can also be applied to DML constructs UPDATE, INSERT and DELETE on some databases, both as a source of CTE rows when combined with RETURNING, as well as a consumer of CTE rows.

    SQLAlchemy detects `CTE` objects, which are treated similarly to `Alias` objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.

    Changed in version 1.1: Added support for UPDATE/INSERT/DELETE as CTE, CTEs added to UPDATE/INSERT/DELETE.

    Parameters: | name – name given to the common table expression. Like `_FromClause.alias()`, the name can be left as `None` in which case an anonymous symbol will be used at query compile time. recursive – if `True`, will render `WITH RECURSIVE`. A recursive common table expression is intended to be used in conjunction with UNION ALL in order to derive rows from those already selected.

    The following examples include two from PostgreSQL’s documentation at http://www.postgresql.org/docs/current/static/queries-with.html, as well as additional examples.

    Example 1, non recursive:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        orders = Table('orders', metadata,
            Column('region', String),
            Column('amount', Integer),
            Column('product', String),
            Column('quantity', Integer)
        )

        regional_sales = select([
                            orders.c.region,
                            func.sum(orders.c.amount).label('total_sales')
                        ]).group_by(orders.c.region).cte("regional_sales")

        top_regions = select([regional_sales.c.region]).\
                where(
                    regional_sales.c.total_sales >
                    select([
                        func.sum(regional_sales.c.total_sales)/10
                    ])
                ).cte("top_regions")

        statement = select([
                    orders.c.region,
                    orders.c.product,
                    func.sum(orders.c.quantity).label("product_units"),
                    func.sum(orders.c.amount).label("product_sales")
            ]).where(orders.c.region.in_(
                select([top_regions.c.region])
            )).group_by(orders.c.region, orders.c.product)

        result = conn.execute(statement).fetchall()

    Example 2, WITH RECURSIVE:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        parts = Table('parts', metadata,
            Column('part', String),
            Column('sub_part', String),
            Column('quantity', Integer),
        )

        included_parts = select([
                            parts.c.sub_part,
                            parts.c.part,
                            parts.c.quantity]).\
                            where(parts.c.part=='our part').\
                            cte(recursive=True)

        incl_alias = included_parts.alias()
        parts_alias = parts.alias()
        included_parts = included_parts.union_all(
            select([
                parts_alias.c.sub_part,
                parts_alias.c.part,
                parts_alias.c.quantity
            ]).
                where(parts_alias.c.part==incl_alias.c.sub_part)
        )

        statement = select([
                    included_parts.c.sub_part,
                    func.sum(included_parts.c.quantity).
                      label('total_quantity')
                ]).\
                group_by(included_parts.c.sub_part)

        result = conn.execute(statement).fetchall()

    Example 3, an upsert using UPDATE and INSERT with CTEs:

        from datetime import date
        from sqlalchemy import (MetaData, Table, Column, Integer,
                                Date, select, literal, and_, exists)

        metadata = MetaData()

        visitors = Table('visitors', metadata,
            Column('product_id', Integer, primary_key=True),
            Column('date', Date, primary_key=True),
            Column('count', Integer),
        )

        # add 5 visitors for the product_id == 1
        product_id = 1
        day = date.today()
        count = 5

        update_cte = (
            visitors.update()
            .where(and_(visitors.c.product_id == product_id,
                        visitors.c.date == day))
            .values(count=visitors.c.count + count)
            .returning(literal(1))
            .cte('update_cte')
        )

        upsert = visitors.insert().from_select(
            [visitors.c.product_id, visitors.c.date, visitors.c.count],
            select([literal(product_id), literal(day), literal(count)])
                .where(~exists(update_cte.select()))
        )

        connection.execute(upsert)

    See also

    `orm.query.Query.cte()` - ORM version of `HasCTE.cte()`.

  `description`
    inherited from the `description` attribute of `FromClause`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `execute`(*multiparams, **params)
    inherited from the `execute()` method of `Executable`

    Compile and execute this `Executable`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `get_children`(**kwargs)
    inherited from the `get_children()` method of `ClauseElement`

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `is_derived_from`(fromclause)
    inherited from the `is_derived_from()` method of `FromClause`

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `label`(name)

    return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.

    See also

    `as_scalar()`.

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `scalar`(*multiparams, **params)
    inherited from the `scalar()` method of `Executable`

    Compile and execute this `Executable`, returning the result’s scalar representation.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.` `TableClause`(name, *columns)

  Bases: `sqlalchemy.sql.expression.Immutable`, `sqlalchemy.sql.expression.FromClause`

  Represents a minimal “table” construct.

  This is a lightweight table object that has only a name and a collection of columns, which are typically produced by the `expression.column()` function:

      from sqlalchemy import table, column

      user = table("user",
              column("id"),
              column("name"),
              column("description"),
      )

  The `TableClause` construct serves as the base for the more commonly used `Table` object, providing the usual set of `FromClause` services including the `.c.` collection and statement generation methods.

  It does not provide all the additional schema-level services of `Table`, including constraints, references to other tables, or support for `MetaData`-level services. It’s useful on its own as an ad-hoc construct used to generate quick SQL statements when a more fully fledged `Table` is not on hand.

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__init__`(name, *columns)

    Construct a new `TableClause` object.

    This constructor is mirrored as a public API function; see `table()` for a full usage and argument description.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(name=None, flat=False)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `delete`(dml, whereclause=None, **kwargs)

    Generate a `delete()` construct against this `TableClause`.

    E.g.:

        table.delete().where(table.c.id==7)

    See `delete()` for argument and usage information.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `get_children`(column_collections=True, **kwargs)

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `implicit_returning` = False

    `TableClause` doesn’t support having a primary key or column -level defaults, so implicit returning doesn’t apply.

  `insert`(dml, values=None, inline=False, **kwargs)

    Generate an `insert()` construct against this `TableClause`.

    E.g.:

        table.insert().values(name='foo')

    See `insert()` for argument and usage information.

  `is_derived_from`(fromclause)
    inherited from the `is_derived_from()` method of `FromClause`

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `update`(dml, whereclause=None, values=None, inline=False, **kwargs)

    Generate an `update()` construct against this `TableClause`.

    E.g.:

        table.update().where(table.c.id==7).values(name='foo')

    See `update()` for argument and usage information.

class `sqlalchemy.sql.expression.` `TableSample`(selectable, sampling, name=None, seed=None)

  Bases: `sqlalchemy.sql.expression.Alias`

  Represent a TABLESAMPLE clause.

  This object is constructed from the `tablesample()` module level function as well as the `FromClause.tablesample()` method available on all `FromClause` subclasses.

  New in version 1.1.

  See also

  `tablesample()`

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(name=None, flat=False)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `description`
    inherited from the `description` attribute of `Alias`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `get_children`(column_collections=True, **kw)
    inherited from the `get_children()` method of `Alias`

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `is_derived_from`(fromclause)
    inherited from the `is_derived_from()` method of `Alias`

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(target=None)
    inherited from the `self_group()` method of `Alias`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.` `TextAsFrom`(text, columns, positional=False)

  Bases: `sqlalchemy.sql.expression.SelectBase`

  Wrap a `TextClause` construct within a `SelectBase` interface.

  This allows the `TextClause` object to gain a `.c` collection and other FROM-like capabilities such as `FromClause.alias()`, `SelectBase.cte()`, etc.

  The `TextAsFrom` construct is produced via the `TextClause.columns()` method - see that method for details.

  New in version 0.9.0.

  See also

  `text()`

  `TextClause.columns()`

  `__eq__`
    inherited from the `__eq__` attribute of `object`

    Return self==value.

  `__le__`
    inherited from the `__le__` attribute of `object`

    Return self<=value.

  `__lt__`
    inherited from the `__lt__` attribute of `object`

    Return self<value.

  `__ne__`
    inherited from the `__ne__` attribute of `object`

    Return self!=value.

  `alias`(name=None, flat=False)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `as_scalar`()
    inherited from the `as_scalar()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, which can be used as a column expression.

    Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.

    The returned object is an instance of `ScalarSelect`.

  `autocommit`()
    inherited from the `autocommit()` method of `SelectBase`

    return a new selectable with the ‘autocommit’ flag set to True.

    Deprecated since version 0.6: `autocommit()` is deprecated. Use `Executable.execution_options()` with the ‘autocommit’ flag.

  `bind`
    inherited from the `bind` attribute of `Executable`

    Returns the `Engine` or `Connection` to which this `Executable` is bound, or None if none found.

    This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(default, bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    - Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`’s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`’s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column. compile_kwargs – optional dictionary of additional parameters that will be passed through to the compiler within all “visit” methods. This allows any custom flag to be passed through to a custom compilation construct, for example. It is also used for the case of passing the `literal_binds` flag through:
          from sqlalchemy.sql import table, column, select

          t = table('t', column('x'))

          s = select([t]).where(t.c.x == 5)

          print s.compile(compile_kwargs={"literal_binds": True})
    New in version 0.9.0.

    See also

    How do I render SQL expressions as strings, possibly with bound parameters inlined?

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(functions, whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

    Deprecated since version 1.1: `FromClause.count()` is deprecated. Counting rows requires that the correct column expression and accommodations for joins, DISTINCT, etc. must be made, otherwise results may not be what’s expected. Please use an appropriate `func.count()` expression directly.

    The function generates COUNT against the first column in the primary key of the table, or against the first column in the table overall. Explicit use of `func.count()` should be preferred:

        row_count = conn.scalar(
            select([func.count('*')]).select_from(table)
        )

    See also

    `func`

  `cte`(name=None, recursive=False)
    inherited from the `cte()` method of `HasCTE`

    Return a new `CTE`, or Common Table Expression instance.

    Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.

    CTEs can also be applied to DML constructs UPDATE, INSERT and DELETE on some databases, both as a source of CTE rows when combined with RETURNING, as well as a consumer of CTE rows.

    SQLAlchemy detects `CTE` objects, which are treated similarly to `Alias` objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.

    Changed in version 1.1: Added support for UPDATE/INSERT/DELETE as CTE, CTEs added to UPDATE/INSERT/DELETE.

    Parameters: | name – name given to the common table expression. Like `_FromClause.alias()`, the name can be left as `None` in which case an anonymous symbol will be used at query compile time. recursive – if `True`, will render `WITH RECURSIVE`. A recursive common table expression is intended to be used in conjunction with UNION ALL in order to derive rows from those already selected.

    The following examples include two from PostgreSQL’s documentation at http://www.postgresql.org/docs/current/static/queries-with.html, as well as additional examples.

    Example 1, non recursive:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        orders = Table('orders', metadata,
            Column('region', String),
            Column('amount', Integer),
            Column('product', String),
            Column('quantity', Integer)
        )

        regional_sales = select([
                            orders.c.region,
                            func.sum(orders.c.amount).label('total_sales')
                        ]).group_by(orders.c.region).cte("regional_sales")

        top_regions = select([regional_sales.c.region]).\
                where(
                    regional_sales.c.total_sales >
                    select([
                        func.sum(regional_sales.c.total_sales)/10
                    ])
                ).cte("top_regions")

        statement = select([
                    orders.c.region,
                    orders.c.product,
                    func.sum(orders.c.quantity).label("product_units"),
                    func.sum(orders.c.amount).label("product_sales")
            ]).where(orders.c.region.in_(
                select([top_regions.c.region])
            )).group_by(orders.c.region, orders.c.product)

        result = conn.execute(statement).fetchall()

    Example 2, WITH RECURSIVE:

        from sqlalchemy import (Table, Column, String, Integer,
                                MetaData, select, func)

        metadata = MetaData()

        parts = Table('parts', metadata,
            Column('part', String),
            Column('sub_part', String),
            Column('quantity', Integer),
        )

        included_parts = select([
                            parts.c.sub_part,
                            parts.c.part,
                            parts.c.quantity]).\
                            where(parts.c.part=='our part').\
                            cte(recursive=True)

        incl_alias = included_parts.alias()
        parts_alias = parts.alias()
        included_parts = included_parts.union_all(
            select([
                parts_alias.c.sub_part,
                parts_alias.c.part,
                parts_alias.c.quantity
            ]).
                where(parts_alias.c.part==incl_alias.c.sub_part)
        )

        statement = select([
                    included_parts.c.sub_part,
                    func.sum(included_parts.c.quantity).
                      label('total_quantity')
                ]).\
                group_by(included_parts.c.sub_part)

        result = conn.execute(statement).fetchall()

    Example 3, an upsert using UPDATE and INSERT with CTEs:

        from datetime import date
        from sqlalchemy import (MetaData, Table, Column, Integer,
                                Date, select, literal, and_, exists)

        metadata = MetaData()

        visitors = Table('visitors', metadata,
            Column('product_id', Integer, primary_key=True),
            Column('date', Date, primary_key=True),
            Column('count', Integer),
        )

        # add 5 visitors for the product_id == 1
        product_id = 1
        day = date.today()
        count = 5

        update_cte = (
            visitors.update()
            .where(and_(visitors.c.product_id == product_id,
                        visitors.c.date == day))
            .values(count=visitors.c.count + count)
            .returning(literal(1))
            .cte('update_cte')
        )

        upsert = visitors.insert().from_select(
            [visitors.c.product_id, visitors.c.date, visitors.c.count],
            select([literal(product_id), literal(day), literal(count)])
                .where(~exists(update_cte.select()))
        )

        connection.execute(upsert)

    See also

    `orm.query.Query.cte()` - ORM version of `HasCTE.cte()`.

  `description`
    inherited from the `description` attribute of `FromClause`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `execute`(*multiparams, **params)
    inherited from the `execute()` method of `Executable`

    Compile and execute this `Executable`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `get_children`(**kwargs)
    inherited from the `get_children()` method of `ClauseElement`

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `is_derived_from`(fromclause)
    inherited from the `is_derived_from()` method of `FromClause`

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False, full=False)
    inherited from the `join()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`.

    E.g.:

        from sqlalchemy import join

        j = user_table.join(address_table,
                        user_table.c.id == address_table.c.user_id)
        stmt = select([user_table]).select_from(j)

    would emit SQL along the lines of:

        SELECT user.id, user.name FROM user
        JOIN address ON user.id = address.user_id

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. isouter – if True, render a LEFT OUTER JOIN, instead of JOIN. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. Implies `FromClause.join.isouter`. New in version 1.1.

    See also

    `join()` - standalone function

    `Join` - the type of object produced

  `label`(name)
    inherited from the `label()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.

    See also

    `as_scalar()`.

  `lateral`(name=None)
    inherited from the `lateral()` method of `FromClause`

    Return a LATERAL alias of this `FromClause`.

    The return value is the `Lateral` construct also provided by the top-level `lateral()` function.

    New in version 1.1.

    See also

    LATERAL correlation - overview of usage.

  `outerjoin`(right, onclause=None, full=False)
    inherited from the `outerjoin()` method of `FromClause`

    Return a `Join` from this `FromClause` to another `FromClause`, with the “isouter” flag set to True.

    E.g.:

        from sqlalchemy import outerjoin

        j = user_table.outerjoin(address_table,
                        user_table.c.id == address_table.c.user_id)

    The above is equivalent to:

        j = user_table.join(
            address_table,
            user_table.c.id == address_table.c.user_id,
            isouter=True)

    Parameters: | right – the right side of the join; this is any `FromClause` object such as a `Table` object, and may also be a selectable-compatible object such as an ORM-mapped class. onclause – a SQL expression representing the ON clause of the join. If left at `None`, `FromClause.join()` will attempt to join the two tables based on a foreign key relationship. full – if True, render a FULL OUTER JOIN, instead of LEFT OUTER JOIN. New in version 1.1.

    See also

    `FromClause.join()`

    `Join`

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(sqlutil, old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `scalar`(*multiparams, **params)
    inherited from the `scalar()` method of `Executable`

    Compile and execute this `Executable`, returning the result’s scalar representation.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `tablesample`(sampling, name=None, seed=None)
    inherited from the `tablesample()` method of `FromClause`

    Return a TABLESAMPLE alias of this `FromClause`.

    The return value is the `TableSample` construct also provided by the top-level `tablesample()` function.

    New in version 1.1.

    See also

    `tablesample()` - usage guidelines and parameters

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.