REGEX_EXTRACT_FIRST

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Returns the first substring matching a regular expression pattern, optionally extracting a specific capture group.

Signatures

Returns: The matched substring, or NULL if no match

REGEX_EXTRACT_FIRST(string: VARCHAR, pattern: VARCHAR, [group_number: BIGINT]) → VARCHAR

sql

Parameter	Type	Required	Description
`string`	`VARCHAR`	Yes	String to search in
`pattern`	`VARCHAR`	Yes	Regular expression pattern (use capture groups for extraction)
`group_number`	`BIGINT`	No	Capture group to return (0 = full match, 1 = first group, etc.). Defaults to 0

Notes

Group 0 (default) returns the entire match
Group 1+ returns the corresponding capture group
Returns NULL if the pattern does not match
Only the first match is returned

Examples

FeatureQL

SELECT
    f1 := REGEX_EXTRACT_FIRST('abc123def', '[0-9]+'),  -- Extract digits
    f2 := REGEX_EXTRACT_FIRST('2024-01-15', '(\d{4})-(\d{2})-(\d{2})', 1),  -- Extract year
    f3 := REGEX_EXTRACT_FIRST('2024-01-15', '(\d{4})-(\d{2})-(\d{2})', 2),  -- Extract month
    f4 := REGEX_EXTRACT_FIRST('2024-01-15', '(\d{4})-(\d{2})-(\d{2})', 3),  -- Extract day
    f5 := REGEX_EXTRACT_FIRST('no match here', '[0-9]+')  -- No match returns empty
;

Result

f1 VARCHAR	f2 VARCHAR	f3 VARCHAR	f4 VARCHAR	f5 VARCHAR
123	2024	01	15	(empty)

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Last update at: 2026/03/03 16:47:38

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