sqlzoo练习13-join-quiz2

sqlzoo练习13-join-quiz2

还是通过下面的3张表进行练习

练习

1. Select the statement which lists the unfortunate directors of the movies which have caused financial loses (gross < budget)

找出毛利小于预算的导演 需要注意的是导演们的名字也是在actor表中的

select name
from actor
inner join movie on actor.id=director    -- actor表中的id和director相同即可
where gross < budget;

1. Select the correct example of JOINing three tables

3个表的联结通过两个Join实现：actor—>casting—>movie

select *
from actor
	join casting on actor.id=actorid
	join movie on movie.id=movieid;

1. Select the statement that shows the list of actors called ‘John’ by order of number of movies in which they acted

找出由名字中包含John的演员的电影（通配符的使用），根据电影数量排序 笔记：order by 排序的时候可以使用字段名字，也可以使用字段的相对位置

select name, count(movieid)   -- 统计数量
from casting
	join actor on actorid=actor.id  -- 两个表的联结
where name like 'John %'
group by name   -- 名字分组
order by 2 desc   -- 2 表示的是第2个字段count(movieid)

1. Select the result that would be obtained from the following code:

选择由该演员出演主角的电影

select title
from movie
	join casting on (movieid=movie.id)
	join actor on   (actorid=actor.id)
where name='Paul Hogen'
and ord=1

image-20200130183611907

1. Select the statement that lists all the actors that starred in movies directed by Ridley Scott who has id 351

找出由RS导演的电影的主演

select name
from movie
	join casting on movie.id=movieid
	join actor on actor.id=actorid
where ord=1  -- 主演
and director = 351   -- 导演编号

1. There are two sensible ways to connect movie and actor. They are:

两种方式将movie和actor表进行联结

• 通过director字段和actor表中的主键相连接
• 通过casting表将另外两个表连接

image-20200130183908556

1. Select the result that would be obtained from the following code:

通过代码选出正确答案

select title, yr
from movie, casting, actor
where name='Robert De Niro'
and movieid=movie.id
and actorid=actor.id
and ord=3   -- 排名第3

image-20200130184344783