六種SQL Server刪除重復(fù)行的方法
SQL Server刪除重復(fù)行是我們最常見的操作之一,下面就為您介紹六種適合不同情況的SQL Server刪除重復(fù)行的方法,供您參考。
1.如果有ID字段,就是具有***性的字段
- delect table where id not in (
- select max(id) from table group by col1,col2,col3...
- )
group by 子句后跟的字段就是你用來判斷重復(fù)的條件,如只有col1,那么只要col1字段內(nèi)容相同即表示記錄相同。
2. 如果是判斷所有字段也可以這樣
- select * into #aa from table group by id1,id2,....
- delete table
- insert into table
- select * from #aa
3. 沒有ID的情況
- select identity(int,1,1) as id,* into #temp from tabel
- delect # where id not in (
- select max(id) from # group by col1,col2,col3...)
- delect table
- inset into table(...)
- select ..... from #temp
4. col1+','+col2+','...col5 聯(lián)合主鍵
- select * from table where col1+','+col2+','...col5 in (
- select max(col1+','+col2+','...col5) from table
- where having count(*)>1
- group by col1,col2,col3,col4
- )
group by 子句后跟的字段就是你用來判斷重復(fù)的條件,如只有col1,那么只要col1字段內(nèi)容相同即表示記錄相同。
5.
- select identity(int,1,1) as id,* into #temp from tabel
- select * from #temp where id in (
- select max(id) from #emp where having count(*)>1 group by col1,col2,col3...)
6.
- select distinct * into #temp from tablename
- delete tablename
- go
- insert tablename select * from #temp Sqlclub
- go
- drop table #temp
以上就是SQL Server刪除重復(fù)行的方法介紹。
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