思路：1.找出所有Action分类的电影
2.作为筛选条件
select
title
,description
from film f1
left join film_category f2 on f1.film_id = f2.film_id
where f1.film_id in (
                    select
                    film_id
                    from film_category f2 
                    left join category c on f2.category_id = c.category_id
                    where name = 'Action'
                )