sql 删除表中的重复记录

遇见了表中存在重复的记录的问题，直接写sql删除时最快的，才不要慢慢的复制到excel表中慢慢的人工找呢

如下sql，找出重复的记录，和重复记录中ID值最小的记录（表中ID为自增长）

select MIN(ID) as id, StructSN ,Date,UserID,StarCount,COUNT(StructSN) as cfrom T_Dor_StructStar where Date >= '20160919'group by StructSN ,Date,UserID,StarCounthaving COUNT(StructSN) > 1

然后就可以直接删除，基本原理就是，找到重复记录的每一条记录，排除掉重复id最小的记录，删除剩余的重复记录。

delete from T_Dor_StructStarwhere ID in (select s.ID from T_Dor_StructStar s,(select MIN(ID) as id, StructSN ,Date,UserID,StarCount,COUNT(StructSN) as cfrom T_Dor_StructStar where Date >= '20160919'group by StructSN ,Date,UserID,StarCounthaving COUNT(StructSN) > 1)awherea.Date = s.Dateand a.StructSN = s.StructSNand a.UserID = s.UserIDand a.StarCount = s.StarCountand a.id != s.ID)

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