选择具有相同ID但在其他列中不同的值

Question

我有这张桌子。

旗下拥有：

Pid Cid
100 1
100 2
200 1
200 3
300 4
400 1
400 4
400 5
500 2
500 4

我只需要选择Cid = 1而不是Cid = 2的Pid，输出应为：

pid
200
400

我的查询是：

SELECT Pid
FROM OWNS 
WHERE Cid = 1 and Cid <> 2

但我得到结果：

pid
100
200
400

Answer 1

尝试

SELECT distinct Pid 
FROM OWNS 
WHERE 
   Pid not in (select Pid from OWNS where Cid = 2) 
AND CID = 1;

Answer 2

或这个：

SELECT `pid` 
FROM `OWNS` 
WHERE `cid` = '1' 
    AND `pid` in (SELECT `pid` 
                  FROM `OWNS` 
                  WHERE `cid` != '1' AND `cid` != '2')