## Syntax
```mermaid
%%{init: {
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'themeVariables': {
'fontSize': '11px',
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flowchart LR
Start((START)) --> IS_BOOLEAN[IS_BOOLEAN]:::quoted
IS_BOOLEAN --> End((END))
```
The `IS_BOOLEAN` SQL function determines whether a value is a valid boolean. When true, the value can be converted by to_boolean.
Parameters:
- Input: value to convert.
Returns: true when the value can be converted to a boolean, false otherwise.