[discrete]
[[esql-to_boolean]]
=== `TO_BOOLEAN`
Converts an input value to a boolean value.

The input can be a single- or multi-valued field or an expression. The input
type must be of a string or numeric type.

A string value of *"true"* will be case-insensitive converted to the Boolean
*true*. For anything else, including the empty string, the function will
return *false*. For example:

[source.merge.styled,esql]
----
include::{esql-specs}/boolean.csv-spec[tag=to_boolean]
----
[%header.monospaced.styled,format=dsv,separator=|]
|===
include::{esql-specs}/boolean.csv-spec[tag=to_boolean-result]
|===

The numerical value of *0* will be converted to *false*, anything else will be
converted to *true*.

Alias: TO_BOOL
