select c.name,count(a.film_id) from film a inner join film_category b on a.film_id = b.film_id inner join category c on c.category_id = b.category_id where a.description like '%robot%' and c.category_id in (SELECT category_id FROM film_category GROUP BY category_id HAVING COUNT(film_id) >= 5);首先能用联结尽量避免用子查询