## Syntax
```mermaid
%%{init: {
'theme': 'base',
'flowchart': { 'padding': '7', 'nodeSpacing': '20', 'rankSpacing': '20' },
'themeVariables': {
'fontSize': '11px',
'fontFamily': 'Arial'
}
}}%%
flowchart LR
Start((START)) --> DOUBLE_METAPHONE[DOUBLE_METAPHONE]:::quoted
DOUBLE_METAPHONE --> End((END))
```
## Purpose
The `DOUBLE_METAPHONE` SQL function converts a value to the Metaphone code as defined on <a href="https://en.wikipedia.org/wiki/Metaphone">Wikipedia</a>.
Parameters:
- Input: value to convert to double metaphone.
Returns: the input converted to double metaphone, with a output length of 4.