mysql - sql请求-多值

Question

我有下表:

userid    title         content
1         gender        male
1         location      NY    
2         gender        female
2         location      SF
3         gender        female
3         location      NY

我正在尝试仅检索具有 gender="male"和 location="NY" 的用户 ID

如果我尝试:

select userid
from table
where content="male"
   AND location="NY";

它将返回空值。 知道怎么做吗？

Answer 1

SELECT t.userId
FROM yourTable AS t
INNER JOIN yourTable AS t2 ON t.userId = t2.userId
   AND t.title = 'gender'
   AND t.content = 'male'
   AND t2.title = 'location'
   AND t2.content = 'NY'

我还会考虑规范化您的数据。这将使将来的查询变得更容易(并且可能更快)。