Find every actor that has appeared in at least 20 rated movies.

gistfile1.sql

SELECT * FROM (
		SELECT actor_id, COUNT(*) as count FROM actors
		JOIN `roles`
		ON actors.`id` = roles.`actor_id`
			JOIN `movies`
			ON movies.`id` = `movie_id`
		WHERE rank IS NOT NULL
		GROUP BY actor_id) a
	WHERE a.count >= 20;