Simulating regex capture groups in mysql

Question

As far as I can tell MySQL does not support retrieving the value of a capture group from a regex match. I have found a server side extensions (lib_mysqludf_preg) which would

Answer 1

After some trial and error I came up with the following query that does what I need. Basically I seperate numbers off the end of the string and then remove that many characters before separating the next number. The version1 column is limited to positive 2 digit numbers, but that that's a limitation that I can live with in my case.

SELECT
    IF(CAST(RIGHT(SUBSTRING_INDEX(LEFT(version,CHAR_LENGTH(version) - CHAR_LENGTH(SUBSTRING_INDEX(version, '.', -3)) - 1), '.', -1),2) AS DECIMAL) > 0, 
        CAST(RIGHT(SUBSTRING_INDEX(LEFT(version,CHAR_LENGTH(version) - CHAR_LENGTH(SUBSTRING_INDEX(version, '.', -3)) - 1), '.', -1),2) AS DECIMAL), 
        CAST(RIGHT(SUBSTRING_INDEX(LEFT(version,CHAR_LENGTH(version) - CHAR_LENGTH(SUBSTRING_INDEX(version, '.', -3)) - 1), '.', -1),1) AS DECIMAL)) AS version1,
    SUBSTRING_INDEX(LEFT(version,CHAR_LENGTH(version) - CHAR_LENGTH(SUBSTRING_INDEX(version, '.', -2)) - 1), '.', -1) as version2,
    SUBSTRING_INDEX(LEFT(version,CHAR_LENGTH(version) - CHAR_LENGTH(SUBSTRING_INDEX(version, '.', -1)) - 1), '.', -1) as version3,
    SUBSTRING_INDEX(version, '.', -1) as version4
FROM Version
HAVING version1 >= 5
;