Question

I need some help cutting the execution time on this query. 7 seconds seems too long for a table with 1500 rows.

  SELECT parent
    FROM video
   WHERE parent NOT IN (SELECT parent
                          FROM video
                         WHERE filename REGEXP '(s[0-9]{2}\e[0-9]{2})|([[:<:]][0-9]{3}[[:>:]])')
GROUP BY parent

Answer 1

First, you can use NOT REGEXP instead of a subquery.

SELECT parent
FROM video
WHERE filename NOT REGEXP '(s[0-9]{2}\e[0-9]{2})|([[:<:]][0-9]{3}[[:>:]])'
GROUP BY parent

When using REGEXP or NOT REGEXP, the indexes don’t matter. To make it more efficient, if that’s still not enough, you’ll have to look at using other string functions or the LIKE operator.