sql 刪除表中的重復記錄

遇見了表中存在重復的記錄的問題，直接寫sql刪除時最快的，才不要慢慢的復制到excel表中慢慢的人工找呢

如下sql，找出重復的記錄，和重復記錄中ID值最小的記錄（表中ID為自增長）

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

然後就可以直接刪除，基本原理就是，找到重復記錄的每一條記錄，排除掉重復id最小的記錄，刪除剩余的重復記錄。

delete from T_Dor_StructStar
where ID in (
select s.ID from T_Dor_StructStar s,
(
select MIN(ID) as id, StructSN ,Date,UserID,StarCount,COUNT(StructSN) as c
from T_Dor_StructStar 
where Date >= '20160919'
group by StructSN ,Date,UserID,StarCount
having COUNT(StructSN) > 1
)a
where
a.Date = s.Date
and a.StructSN = s.StructSN
and a.UserID = s.UserID
and a.StarCount = s.StarCount
and a.id != s.ID
)

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