SQL30 使用子查询的方式找出属于Action分类的所有电影

本文最后更新于：2022年4月9日 中午


题目描述

film表

字段 说明
film_id 电影id
title 电影名称
description 电影描述信息 
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CREATE TABLE IF NOT EXISTS film (
film_id smallint(5)  NOT NULL DEFAULT '0',
title varchar(255) NOT NULL,
description text,
PRIMARY KEY (film_id));

category表

字段 说明
category_id 电影分类id
name 电影分类名称
last_update 电影分类最后更新时间 
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CREATE TABLE category  (
category_id  tinyint(3)  NOT NULL ,
name  varchar(25) NOT NULL, `last_update` timestamp,
PRIMARY KEY ( category_id ));

film_category表

字段 说明
film_id 电影id
category_id 电影分类id
last_update 电影id和分类id对应关系的最后更新时间 
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CREATE TABLE film_category  (
film_id  smallint(5)  NOT NULL,
category_id  tinyint(3)  NOT NULL, `last_update` timestamp);

你能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吗

如插入：

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INSERT INTO film VALUES(1,'ACADEMY DINOSAUR','A Epic Drama of a Feminist And a Mad Scientist who must Battle a Teacher in The Canadian Rockies');
INSERT INTO film VALUES(2,'ACE GOLDFINGER','A Astounding Epistle of a Database Administrator And a Explorer who must Find a Car in Ancient China');
INSERT INTO film VALUES(3,'ADAPTATION HOLES','A Astounding Reflection of a Lumberjack And a Car who must Sink a Lumberjack in A Baloon Factory');

INSERT INTO category VALUES(1,'Action','2006-02-14 20:46:27');
INSERT INTO category VALUES(2,'Animation','2006-02-14 20:46:27');
INSERT INTO category VALUES(3,'Children','2006-02-14 20:46:27');
INSERT INTO category VALUES(4,'Classics','2006-02-14 20:46:27');
INSERT INTO category VALUES(5,'Comedy','2006-02-14 20:46:27');
INSERT INTO category VALUES(6,'Documentary','2006-02-14 20:46:27');

INSERT INTO film_category VALUES(1,1,'2006-02-14 21:07:09');
INSERT INTO film_category VALUES(2,1,'2006-02-14 21:07:09');
INSERT INTO film_category VALUES(3,6,'2006-02-14 21:07:09');

输入描述

无

输出描述

title description
ACADEMY DINOSAUR A Epic Drama of a Feminist And a Mad Scientist who must Battle a Teacher in The Canadian Rockies
ACE GOLDFINGER A Astounding Epistle of a Database Administrator And a Explorer who must Find a Car in Ancient China

题解

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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'))
或
select f.title,f.description 
from film as f inner join film_category as fc on f.film_id = fc.film_id
               inner join category as c on c.category_id = fc.category_id
where c.name = 'Action';

备注：

  1. 方法一：子查询
  2. 方法二：多表连接