The Ultimate Guide to High Availability with MariaDB
This is a read-only copy of the MariaDB Knowledgebase generated on 2024-11-14. For the latest, interactive version please visit https://mariadb.com/kb/.

REGEXP

Syntax

expr REGEXP pat, expr RLIKE pat

Description

Performs a pattern match of a string expression expr against a pattern pat. The pattern can be an extended regular expression. See Regular Expressions Overview for details on the syntax for regular expressions (see also PCRE Regular Expressions).

Returns 1 if expr matches pat or 0 if it doesn't match. If either expr or pat are NULL, the result is NULL.

The negative form NOT REGEXP also exists, as an alias for NOT (string REGEXP pattern). RLIKE and NOT RLIKE are synonyms for REGEXP and NOT REGEXP, originally provided for mSQL compatibility.

The pattern need not be a literal string. For example, it can be specified as a string expression or table column.

Note: Because MariaDB uses the C escape syntax in strings (for example, "\n" to represent the newline character), you must double any "\" that you use in your REGEXP strings.

REGEXP is not case sensitive, except when used with binary strings.

MariaDB 10.0.5 moved to the PCRE regex library - see PCRE Regular Expressions for enhancements to REGEXP introduced in MariaDB 10.0.5.

The default_regex_flags variable addresses the remaining compatibilities between PCRE and the old regex library.

Examples

SELECT 'Monty!' REGEXP 'm%y%%';
+-------------------------+
| 'Monty!' REGEXP 'm%y%%' |
+-------------------------+
|                       0 |
+-------------------------+

SELECT 'Monty!' REGEXP '.*';
+----------------------+
| 'Monty!' REGEXP '.*' |
+----------------------+
|                    1 |
+----------------------+

SELECT 'new*\n*line' REGEXP 'new\\*.\\*line';
+---------------------------------------+
| 'new*\n*line' REGEXP 'new\\*.\\*line' |
+---------------------------------------+
|                                     1 |
+---------------------------------------+

SELECT 'a' REGEXP 'A', 'a' REGEXP BINARY 'A';
+----------------+-----------------------+
| 'a' REGEXP 'A' | 'a' REGEXP BINARY 'A' |
+----------------+-----------------------+
|              1 |                     0 |
+----------------+-----------------------+

SELECT 'a' REGEXP '^[a-d]';
+---------------------+
| 'a' REGEXP '^[a-d]' |
+---------------------+
|                   1 |
+---------------------+

default_regex_flags examples

MariaDB 10.0.11 introduced the default_regex_flags variable to address the remaining compatibilities between PCRE and the old regex library.

The default behaviour (multiline match is off)

SELECT 'a\nb\nc' RLIKE '^b$';
+---------------------------+
| '(?m)a\nb\nc' RLIKE '^b$' |
+---------------------------+
|                         0 |
+---------------------------+

Enabling the multiline option using the PCRE option syntax:

SELECT 'a\nb\nc' RLIKE '(?m)^b$';
+---------------------------+
| 'a\nb\nc' RLIKE '(?m)^b$' |
+---------------------------+
|                         1 |
+---------------------------+

Enabling the multiline option using default_regex_flags

SET default_regex_flags='MULTILINE';
SELECT 'a\nb\nc' RLIKE '^b$';
+-----------------------+
| 'a\nb\nc' RLIKE '^b$' |
+-----------------------+
|                     1 |
+-----------------------+
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