其中A = 1 AND A = 2返回0行问题-(简短的MySQL问题) [英] Where A=1 AND A=2 returns 0 row problem - (Short Mysql question)

问题描述

我有下表(id, Tag)和以下值

(1, 17)
(1, 31)
(2, 17)
(3, 31)

当我查询以下内容

"SELECT id FROM table WHERE 1 AND Tag=17 AND Tag=31"

我希望它返回(id)

(1)

但事实并非如此. (返回0行)

But it doesn't. (returns 0 row)

这是怎么了?

推荐答案

对于任何特定行，标记不能同时为17和31.

For any particular row the tag can't be both 17 and 31. You need

SELECT id 
FROM   table 
WHERE  Tag in (17, 31) 
GROUP  BY id 
HAVING COUNT(DISTINCT Tag) = 2  

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