SQL29 使用join查询方式找出没有分类的电影id以及名称

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

 

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

 

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

输入：

drop table if exists  film ;
drop table if exists  category  ; 
drop table if exists  film_category  ; 
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));
CREATE TABLE category  (
   category_id  tinyint(3)  NOT NULL ,
   name  varchar(25) NOT NULL, `last_update` timestamp,
  PRIMARY KEY ( category_id ));
CREATE TABLE film_category  (
   film_id  smallint(5)  NOT NULL,
   category_id  tinyint(3)  NOT NULL, `last_update` timestamp);
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 category VALUES(7,'Drama','2006-02-14 20:46:27');

INSERT INTO category VALUES(8,'Family','2006-02-14 20:46:27');

INSERT INTO category VALUES(9,'Foreign','2006-02-14 20:46:27');

INSERT INTO category VALUES(10,'Games','2006-02-14 20:46:27');

INSERT INTO category VALUES(11,'Horror','2006-02-14 20:46:27');
INSERT INTO film_category VALUES(1,6,'2006-02-14 21:07:09');

INSERT INTO film_category VALUES(2,11,'2006-02-14 21:07:09');

 

使用join查询方式找出没有分类的电影id以及名称

3|ADAPTATION HOLES

SELECT film.film_id,film.title FROM film 
LEFT JOIN film_category ON 
film.film_id = film_category.film_id
WHERE film_category.category_id IS NULL