EC
1965
MySQLERRORCommonQueryMEDIUM confidence

Error in regular expression

Production Risk

Low — query is rejected.

What this means

A regular expression passed to REGEXP or REGEXP_LIKE is syntactically invalid. MySQL uses the ICU regular expression library in 8.0 and the POSIX library in earlier versions.

Why it happens
  1. 1Unmatched parentheses or brackets in a REGEXP pattern.
  2. 2Invalid escape sequences in the regex pattern.
  3. 3Using Perl-style regex features not supported by the engine in use.
How to reproduce
trigger — this will error
trigger — this will error
SELECT 'hello' REGEXP '[unclosed';

expected output

ERROR 1965 (HY000): Got error 'Missing ']'' from regexp.

Fix

Fix the regular expression syntax

Fix the regular expression syntax
SELECT 'hello' REGEXP '^h[a-z]+o
#x27;;

Why this works

Validate the regex pattern before use; online tools like regex101.com can help debug patterns.

Version notes

Sources
Official documentation ↗

MySQL 8.0 — 1965 ER_SYNTAX_ERROR_OR_ACCESS_VIOLATION_IN_EXCEPT

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