# Regular Expressions Functions

- [Regular Expressions Overview](/docs/server/reference/sql-functions/string-functions/regular-expressions-functions/regular-expressions-overview.md): Get an overview of regex usage. This page introduces the pattern matching capabilities and common metacharacters used in MariaDB regular expressions.
- [PCRE - Perl Compatible Regular Expressions](/docs/server/reference/sql-functions/string-functions/regular-expressions-functions/pcre.md): Understand MariaDB's regex support. This concept page explains the PCRE library integration, detailing supported syntax, character classes, and special characters.
- [REGEXP](/docs/server/reference/sql-functions/string-functions/regular-expressions-functions/regexp.md): Complete REGEXP operator reference: expr REGEXP/RLIKE pat syntax, 1/0/NULL return values, NOT REGEXP aliases, BINARY case-sensitivity, default\_regex\_flags.
- [REGEXP\_INSTR](/docs/server/reference/sql-functions/string-functions/regular-expressions-functions/regexp_instr.md): Return the index of a regex match. This function finds the starting position of the first substring that matches the given pattern.
- [REGEXP\_REPLACE](/docs/server/reference/sql-functions/string-functions/regular-expressions-functions/regexp_replace.md): Replace regex matches in a string. This function substitutes occurrences of a pattern with a specified replacement string.
- [REGEXP\_SUBSTR](/docs/server/reference/sql-functions/string-functions/regular-expressions-functions/regexp_substr.md): Return the substring matching a regex. This function extracts the actual part of the string that matches the given pattern.
- [RLIKE](/docs/server/reference/sql-functions/string-functions/regular-expressions-functions/rlike.md): Synonym for REGEXP. This operator performs a regular expression match against a string argument.