嗯 多字段查找和删除重复数据。 in 语句在SQL Server 里面不能有多个字段的 所以用inner join 可以 0
select * from CET4Grade a inner join
(select SJXQ,XQ,StudentID from dbo.CET4Grade
group by SJXQ,XQ,StudentID having count(*)>1)
b on a.SJXQ=b.SJXQ and a.XQ=b.XQ and a.StudentID=b.StudentID
删除 嗯 用exists
Delete t from dbo.CET4Grade t where exists
(
select SJXQ,XQ,StudentID from CET4Grade
group by SJXQ,XQ,StudentID having count(*)>1 and SJXQ=t.SJXQ and XQ=t.XQ and StudentID=t.StudentID
)