题解 | #使用子查询的方式找出属于Action分类的所有电影对应的title,description#

select title, description
from film
where film_id in
(select film_id
from film_category
where category_id in
(select category_id
from category
where name = 'Action'));

解题思路 从内到外，依次嵌套。

-- 第一步：找出Action对应的category_id
select category_id
from category
where name = 'Action';

-- 第二步：找出category_id对应的film_id
select film_id
from film_category
where category_id in
(select category_id
from category
where name = 'Action');

-- 第三步： 找出film_id对应的title,description
select title, description
from film
where film_id in
(select film_id
from film_category
where category_id in
(select category_id
from category
where name = 'Action'));