---
title: SQL regular expression functions
description: Use regular expression functions to operate on data in SQL queries.
url: https://docs.influxdata.com/influxdb3/cloud-dedicated/reference/sql/functions/regular-expression/
estimated_tokens: 1511
publisher: InfluxData
canonical: https://docs.influxdata.com/influxdb3/cloud-dedicated/reference/sql/functions/regular-expression/
date: '2025-09-05T08:26:38-06:00'
lastmod: '2025-09-05T08:26:38-06:00'
---

The InfluxDB Cloud Dedicated SQL implementation uses the[PCRE-like](https://en.wikibooks.org/wiki/Regular_Expressions/Perl-Compatible_Regular_Expressions)regular expression [syntax](https://docs.rs/regex/latest/regex/#syntax)(excluding some features such as look-around and back-references) and supports
the following regular expression functions:

* [regexp\_count](#regexp_count)
* [regexp\_like](#regexp_like)
* [regexp\_match](#regexp_match)
* [regexp\_replace](#regexp_replace)

## regexp\_count

Returns the number of matches that a regular expression has in a string.

```sql
regexp_count(str, regexp[, start, flags])
```

### Arguments

* **str**: String expression to operate on.
  Can be a constant, column, or function, and any combination of operators.
* **regexp**: Regular expression to operate on.
  Can be a constant, column, or function, and any combination of operators.
* **start**: Optional start position (the first position is 1) to search for the regular expression.
  Can be a constant, column, or function.
* **flags**: Optional regular expression flags that control the behavior of the
  regular expression. The following flags are supported:
  * **i**: (insensitive) Ignore case when matching.
  * **m**: (multi-line) `^` and `$` match the beginning and end of a line, respectively.
  * **s**: (single-line) `.` matches newline (`\n`).
  * **R**: (CRLF) When multi-line mode is enabled, `\r\n` is used to delimit lines.
  * **U**: (ungreedy) Swap the meaning of `x*` and `x*?`.

[](#view-regexp_count-query-example)

View `regexp_count` query example

*The following example uses the [Get started home sensor sample data](/influxdb3/cloud-dedicated/reference/sample-data/#get-started-home-sensor-data).*

```sql
SELECT DISTINCT
  room,
  regexp_count(room::STRING, '[Ro]', 1, 'i') AS regexp_count
FROM home
```

|   room    |regexp\_count|
|-----------|-------------|
|  Kitchen  |      0      |
|Living Room|      3      |

## regexp\_like

True if a regular expression has at least one match in a string;
false otherwise.

```sql
regexp_like(str, regexp[, flags])
```

### Arguments

* **str**: String expression to operate on.
  Can be a constant, column, or function, and any combination of string operators.
* **regexp**: Regular expression to test against the string expression.
  Can be a constant, column, or function.
* **flags**: Optional regular expression flags that control the behavior of the
  regular expression. The following flags are supported:
  * **i**: (insensitive) Ignore case when matching.
  * **m**: (multi-line) `^` and `$` match the beginning and end of a line, respectively.
  * **s**: (single-line) `.` matches newline (`\n`).
  * **R**: (CRLF) When multi-line mode is enabled, `\r\n` is used to delimit lines.
  * **U**: (ungreedy) Swap the meaning of `x*` and `x*?`.

[](#view-regexp_like-query-example)

View `regexp_like` query example

*The following example uses the [Get started home sensor sample data](/influxdb3/cloud-dedicated/reference/sample-data/#get-started-home-sensor-data).*

```sql
SELECT DISTINCT
  room,
  regexp_like(room::STRING, 'R', 'i') AS regexp_like
FROM home
```

|   room    |regexp\_like|
|-----------|------------|
|  Kitchen  |   false    |
|Living Room|    true    |

## regexp\_match

Returns a list of regular expression matches in a string.

```sql
regexp_match(str, regexp, flags)
```

### Arguments

* **str**: String expression to operate on.
  Can be a constant, column, or function, and any combination of string operators.
* **regexp**: Regular expression to match against.
  Can be a constant, column, or function.
* **flags**: Regular expression flags that control the behavior of the
  regular expression. The following flags are supported.
  * **i**: (insensitive) Ignore case when matching.

[](#view-regexp_match-query-example)

View `regexp_match` query example

*The following example uses the [Get started home sensor sample data](/influxdb3/cloud-dedicated/reference/sample-data/#get-started-home-sensor-data).*

> [!Note]
> `regexp_match` returns a *list* Arrow type.
> Use *bracket notation* to reference a value in the list.
> Lists use 1-based indexing.

```sql
SELECT DISTINCT
  room,
  regexp_match(room::STRING, '.{3}')[1] AS regexp_match
FROM home
```

|   room    |regexp\_match|
|-----------|-------------|
|  Kitchen  |     Kit     |
|Living Room|     Liv     |

## regexp\_replace

Replaces substrings in a string that match a regular expression.

```sql
regexp_replace(str, regexp, replacement, flags)
```

### Arguments

* **str**: String expression to operate on.
  Can be a constant, column, or function, and any combination of string operators.
* **regexp**: Regular expression to match against.
  Can be a constant, column, or function.
* **replacement**: Replacement string expression.
  Can be a constant, column, or function, and any combination of string operators.
* **flags**: Regular expression flags that control the behavior of the
  regular expression. The following flags are supported.
  * **g**: (global) Search globally and don’t return after the first match.
  * **i**: (insensitive) Ignore case when matching.

[](#view-regexp_replace-query-example)

View `regexp_replace` query example

*The following example uses the [Get started home sensor sample data](/influxdb3/cloud-dedicated/reference/sample-data/#get-started-home-sensor-data).*

```sql
SELECT DISTINCT
  room,
  regexp_replace(room::STRING, '\sRoom', '', 'gi') AS regexp_replace
FROM home
```

|   room    |regexp\_replace|
|-----------|---------------|
|  Kitchen  |    Kitchen    |
|Living Room|    Living     |
| room | regexp_count |
| --- | --- |
| room | regexp_count |
| Kitchen | 0 |
| Living Room | 3 |

| room | regexp_like |
| --- | --- |
| room | regexp_like |
| Kitchen | false |
| Living Room | true |

| room | regexp_match |
| --- | --- |
| room | regexp_match |
| Kitchen | Kit |
| Living Room | Liv |

| room | regexp_replace |
| --- | --- |
| room | regexp_replace |
| Kitchen | Kitchen |
| Living Room | Living |