## Syntax
```mermaid
%%{init: {
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'flowchart': { 'padding': '7', 'nodeSpacing': '20', 'rankSpacing': '20' },
'themeVariables': {
'fontSize': '11px',
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flowchart LR
Start((START)) --> IS_GUID[IS_GUID]:::quoted
IS_GUID --> End((END))
```
The `IS_GUID` SQL function determines whether a value is a valid GUID. When true, the value can be converted by to_guid.
Parameters:
- Input: value to convert.
Returns: true when the value can be converted to a GUID, false otherwise.