How to compare version string (“x.y.z”) in MySQL?

Question

I have firmware version strings into my table (like \"4.2.2\" or \"4.2.16\")

How can I compare, select or sort them ?

I cannot use standard strings compariso

Answer 1

Lots of good solutions here, but I wanted a stored function that would work with ORDER BY

CREATE FUNCTION standardize_version(version VARCHAR(255)) RETURNS varchar(255) CHARSET latin1 DETERMINISTIC NO SQL
BEGIN
  DECLARE tail VARCHAR(255) DEFAULT version;
  DECLARE head, ret VARCHAR(255) DEFAULT NULL;

  WHILE tail IS NOT NULL DO 
    SET head = SUBSTRING_INDEX(tail, '.', 1);
    SET tail = NULLIF(SUBSTRING(tail, LOCATE('.', tail) + 1), tail);
    SET ret = CONCAT_WS('.', ret, CONCAT(REPEAT('0', 3 - LENGTH(CAST(head AS UNSIGNED))), head));
  END WHILE;

  RETURN ret;
END|

to test:

SELECT standardize_version(version) FROM (SELECT '1.2.33.444.5b' AS version UNION SELECT '1' UNION SELECT NULL) AS t;

renders:

00001.00002.00033.00444.00005b
00001
(null)

And allows for comparisons of almost any set of versions, even ones with letters.