sql查询重复信息

来源:百度知道 编辑:UC知道 时间:2024/05/11 02:39:12
SELECT Vehiclesign
FROM [order]
GROUP BY Vehiclesign
HAVING (COUNT(Vehiclesign) > 1)可以查到信息
为何
SELECT Vehiclesign, only_id
FROM [order]
GROUP BY Vehiclesign, only_id
HAVING (COUNT(Vehiclesign) > 1)查不到信息
请高手指点
那想显示所有列但只有Vehiclesign 是相同的怎么写 啊?

GROUP BY Vehiclesign 分组 Vehiclesign一样的!
GROUP BY Vehiclesign, only_id 分组 Vehiclesign一样的并且Vehiclesign一样的记录中的only_id也必须一样,才进行!

应为GROUP BY Vehiclesign, only_id 之后没有相同的记录,所以COUNT(Vehiclesign)只能=1所以不会显示