Regular Expression Functions

Regular expression functions use RE2 as the regex engine. RE2 is fast, but supports only a subset of PCRE syntax and in particular does not support backtracking and associated features (e.g. back references). See https://github.com/google/re2/wiki/Syntax for more information.

regexp_extract(string, pattern) → varchar

Returns the first substring matched by the regular expression pattern in string.

SELECT regexp_extract('1a 2b 14m', '\d+'); -- 1

regexp_extract(string, pattern, group) → varchar

Finds the first occurrence of the regular expression pattern in string and returns the capturing group number group.

SELECT regexp_extract('1a 2b 14m', '(\d+)([a-z]+)', 2); -- 'a'

rlike(string, pattern) → boolean

Evaluates the regular expression pattern and determines if it is contained within string.

This function is similar to the LIKE operator, except that the pattern only needs to be contained within string, rather than needing to match all of string. In other words, this performs a contains operation rather than a match operation. You can match the entire string by anchoring the pattern using ^ and $.

SELECT rlike('1a 2b 14m', '\d+b'); -- true