## Syntax
```mermaid
%%{init: {
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'themeVariables': {
'fontSize': '11px',
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flowchart LR
Start((START)) --> METAPHONE3_ALT[METAPHONE3_ALT]:::quoted
METAPHONE3_ALT --> End((END))
```
## Purpose
The `METAPHONE3_ALT` SQL function converts a value to the alternate Metaphone 3 code, the third generation of the Metaphone algorithm as defined on [Wikipedia](https://en.wikipedia.org/wiki/Metaphone). The alternate code is only available for values which can be pronounced in multiple ways; otherwise `null` is returned.
See also [[METAPHONE]], [[METAPHONE3]], [[DMETAPHONE_ALT]] and [[SOUNDEX]].
Parameters:
- Input (`varchar2`): value to convert to the alternate Metaphone 3 code.
Returns: the alternate Metaphone 3 code of the input as `varchar2`. Returns `null` when no alternate encoding exists.
## Examples
The following example retrieves the alternate Metaphone 3 code of `Smith`, which is different from the primary Metaphone 3 code `SM0`:
```sql
select metaphone3_alt('Smithe')
-------------------
XMAT
```
The following example retrieves the alternate Metaphone 3 code of `Alfred Johnson`; the output is empty since no alternate encoding exists:
```sql
select metaphone3_alt('Alfred Johnson')
-------------------
```