[Yandex Cloud documentation](../../index.md) > [Yandex DataLens](../index.md) > Calculated fields > Function reference > String functions > REGEXP_EXTRACT_NTH

# REGEXP_EXTRACT_NTH



#### Syntax {#syntax}


```
REGEXP_EXTRACT_NTH( string, pattern, match_index )
```

#### Description {#description}
Returns a substring `string` that matches the regular expression pattern `pattern` starting from the specified index.

**Argument types:**
- `string` — `String`
- `pattern` — `String`
- `match_index` — `Integer`


**Return type**: `String`

{% note info %}

Only constant values are accepted for the arguments (`pattern`).

{% endnote %}

{% note info %}

See the documentation of the data source to clarify the regular expression syntax. For example, `ClickHouse` uses the [RE2 syntax](https://github.com/google/re2/wiki/Syntax) to compose regular expressions.

{% endnote %}


#### Example {#examples}

```
REGEXP_EXTRACT_NTH("RU 912 EN 873", "[A-Z]+\s+(\d+)", 2) = "873"
```


#### Data source support {#data-source-support}

`ClickHouse 21.8`, `Files`, `Google Sheets`, `MySQL 8.0.12`, `Oracle Database 12c (12.1)`, `PostgreSQL 9.3`, `Trino`, `Yandex Documents`.