MySQL的非单调查询

Question

使用下面的数据库模式，发现其作用只是啤酒（S）乔喜欢

Beers(name, manf) 
Bars(name, addr, license) 
Drinkers(name, addr, phone) 
Likes(drinker, beer) 
Sells(bar, beer, price) 
Frequents(drinker, bar) 

这条是我的尝试：

SELECT b.name 
FROM bars b 
WHERE NOT EXISTS 
    (SELECT l.beer 
    FROM likes l 
    WHERE l.drinker = 'joe' AND NOT EXISTS 
     (SELECT * 
     FROM sells s 
     WHERE l.beer = s.beer AND b.name = s.bar)) 

我试图返回酒吧，其中为啤酒乔喜欢，而不是只喜欢啤酒的酒吧。 任何帮助到哪里我错了会很有帮助

Answer 1

可能是这些酒吧

select bar 
from Sells not in (
     select bar 
     from Sells 
     where beer not in (select beer from likes where drinker = 'joe') 
)