架构
Movie(title, year, director, budget, earnings)
Actor(stagename, realname, birthyear)
ActedIn(stagename, title, year, pay)
CanWorkWith(stagename, director)
我需要找到从未在电影中获利的所有演员(舞台名称和真实姓名)(收入>预算).找到所有坏人:P
SELECT A.stagename, A.realname
FROM Actor A
WHERE A.stagename NOT IN
(SELECT B.stagename
FROM ActedIN B
WHERE EXIST
(SELECT *
FROM Movie M
WHERE M.earnings > M.budget AND M.title = B.title AND M.year))
这会找到其stagename没有出现在第二个查询中的所有actor吗?第二个查询将找到在电影中起作用的所有舞台名称.
它是否正确?
最佳答案
SELECT
a.stagename,
a.realname
FROM
Actor a
LEFT JOIN
ActedIn b ON a.stagename = b.stagename
LEFT JOIN
Movie c ON b.title = c.title
AND a.year = b.year
AND c.earnings >= c.budget
WHERE
c.title IS NULL
GROUP BY
a.stagename,
a.realname
– 没有子查询
– 对从未参演过电影的演员的支持
– 根据需要访问聚合函数.