## Syntax
```mermaid
%%{init: {
'theme': 'base',
'flowchart': { 'padding': '7', 'nodeSpacing': '20', 'rankSpacing': '20' },
'themeVariables': {
'fontSize': '11px',
'fontFamily': 'Arial'
}
}}%%
flowchart LR
Start((START)) --> TO_BOOLEAN[TO_BOOLEAN]:::quoted
TO_BOOLEAN --> End((END))
```
## Purpose
The `TO_BOOLEAN` SQL function casts a value into a `boolean`. Non-castable values raise an error; prevent such an error by first checking the value using [[IS_BOOLEAN]].
For numbers `0` is considered `false` and all other values `true`. All `datetime` are `false`. For texts, the following are considered `true`: `'true'`, `'t'`, `'yes'`, `'y'`, `'on'`, `'1'`, `'True'`, `'TRUE'`, `'T'`, `'YES'`, `'Y'` and `'ON'`. False are `'false'`, `'f'`, `'no'`, `'n'`, `'off'`, `'0'`, `'False'`, `'FALSE'`, `'F'`, `'NO'`, `'N'` and `'OFF'`.
Parameters:
- Input (`ANY`): value to cast.
Returns: the input cast as a `boolean`.
## Examples
The following example casts the text `'true'` to a boolean:
```sql
select to_boolean('true')
----------------
true
```
The following example raises an error:
```sql
select to_boolean('tr')
```