Question

这是我的代码，稍后我会把它放到php中，但暂时我在提供的Query测试器中使用它。我们正在做第一个凯文培根而不是第六个。

我的查询如下：

SELECT name,year
FROM actors
JOIN roles ON roles.actor_id = actors.id
JOIN movies ON movies.id=roles.movie_id
WHERE actors.first_name= 'kevin' AND actors.last_name='bacon' OR actors.first_name= 'sean' AND actors.last_name='penn'
ORDER BY movies.name;

导致

Animal House 1978
Apollo 13 1995 
Few Good Men, A 1992 
Footloose 1984 
Hollow Man 2000 
JFK 1991 
Mystic River 2003 
Mystic River 2003 
Planes, Trains & Automobiles 1987 
Stir of Echoes 1999

如何让它只展示神秘河？

Answer 1

首先，将条件分组

WHERE (actors.first_name= 'kevin' AND actors.last_name='bacon') OR 
      (actors.first_name= 'sean' AND actors.last_name='penn')

其次，在DISTINCT关键字

之后添加SELECT

SELECT DISTINCT ...

后续问题：为什么您只想展示Mystic River？

Answer 2

我认为你在这里要求的是DISTINCT ......

DISTINCT关键字可用于仅返回不同的（不同的）值。

试试这个

SELECT DISTINCT name,year
FROM actors
JOIN roles ON roles.actor_id = actors.id
JOIN movies ON movies.id=roles.movie_id
WHERE (actors.first_name= 'kevin' AND actors.last_name='bacon') OR (actors.first_name= 'sean' AND actors.last_name='penn')
ORDER BY movies.name;

和where where子句，

 WHERE (actors.first_name= 'kevin' AND actors.last_name='bacon') AND (actors.first_name= 'sean' AND actors.last_name='penn')

如果你想知道Kevin Bacon和Sean Penn在同一部电影中的位置

Answer 3

如果我理解您的问题，您正在尝试查找其中包含Sean Penn和Kevin Bacon的电影列表。如果是这样，那么您需要在查询中两次使用actors和roles表。

SELECT
    movies.name,
    movies.year
FROM
    actors AS actor2 INNER JOIN roles AS role2 ON actor2.ID = role2.actor_id
           INNER JOIN actors AS actor1 INNER JOIN roles AS role1 ON actor1.ID = role1.actor_id
                INNER JOIN movies ON role1.movie_id = movies.ID ON role2.movie_id = movies.ID
WHERE
    actor1.first_name= 'kevin' AND actor1.last_name='bacon'
        AND
    actor2.first_name= 'sean' AND actor2.last_name='penn'
ORDER BY movies.name;

Answer 4

试试这个

SELECT DISTINCT name,year
FROM actors
JOIN roles ON roles.actor_id = actors.id
JOIN movies ON movies.id=roles.movie_id
WHERE actors.first_name= 'kevin' AND actors.last_name='bacon' OR actors.first_name= 'sean' AND actors.last_name='penn'
ORDER BY movies.name;

只获得相同的结果才能出现在SQL中

4 个答案: