询问一个属性i包含两次的行

Question

有谁知道如何获得SCId出现两次相同数字的行？

Answer 1

一种方法是通过加入子查询来过滤掉非匹配记录，该子查询会查找表中出现两次的所有匹配SCId值。

SELECT t1.*
FROM yourTable t1
INNER JOIN
(
    SELECT SCId
    FROM yourTable
    GROUP BY SCId
    HAVING COUNT(*) = 2
) t2
    ON t1.SCId = t2.SCId;