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刪除重復記錄的SQL語句

2024-07-21 02:50:47
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刪除重復記錄的SQL語句1.所有字段均重復的記錄(重復記錄保留一條)

Select distinct * into #Tmp from tblName

Drop table tblName

Select * into tblName from #Tmp

Drop table #Tmp

設計不周產生的,增加唯一索引可解決

2.所有字段均重復的記錄(重復記錄保留一條)

Select distinct * into #Tmp from tblName

Drop table tblName

Select * into tblName from #Tmp

Drop table #Tmp

設計不周產生的,增加唯一索引可解決

3.保留ID最小的記錄,刪除其它行

Delete from tblName where ID not in (select min(ID) from tblName group Name)

Delete from tblName t inner join (select min(ID) id,Name from tblName group by Name) b on t.name=b.name and t.id<>b.id

Delete from tblName where exists (select * from tblName where name=t.name and id<t.id)

4.只保留ID最大的記錄

  1. Delete from tblName where ID not in (select max(ID) from tblName group by Name having count(*)>1)
  2. Delete from tblName t inner join (select Name,max(ID) id from tblName group by name) b on t.name=b.name and t.id<>b.id
  3. Delete from tblName t where exists (select * from tblName where name=t.name and id>t.id)

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