## Syntax
```mermaid
%%{init: {
'theme': 'base',
'flowchart': { 'padding': '7', 'nodeSpacing': '20', 'rankSpacing': '20' },
'themeVariables': {
'fontSize': '11px',
'fontFamily': 'Arial'
}
}}%%
flowchart LR
Start((START)) --> LEVENSHTEIN[LEVENSHTEIN]:::quoted
LEVENSHTEIN --> End((END))
```
## Purpose
The `LEVENSHTEIN` SQL function determines the Levenshtein distance between two values as defined on [Wikipedia](https://en.wikipedia.org/wiki/Levenshtein_distance). A substitution of one character counts as two steps: a deletion plus an insertion.
Parameters:
- Text 1 (`varchar2`): the first value.
- Text 2 (`varchar2`): the second value.
Returns: the Levenshtein distance as `int32`. Returns `null` when one of the values is `null` or empty.
## Examples
The following example retrieves the Levenshtein distance between `test` and `teste`, requiring one insertion:
```sql
select levenshtein('test', 'teste')
-------------------
1
```
The following example retrieves the Levenshtein distance between `1234` and `4567`; the three deletions plus three insertions total six steps:
```sql
select levenshtein('1234', '4567')
-------------------
6
```
The following example retrieves the Levenshtein distance between two identical values:
```sql
select levenshtein('pete', 'pete')
-------------------
0
```