#3个电影
#6个类别
#3个film_category 记录
select  t2.title,t2.description 
from
              (select a.film_id
                from film_category a
                         join category b
                              on a.category_id = b.category_id
                where b.name = 'Action'
                ) t1 join film t2
on t1.film_id=t2.film_id;