SQL Server删除重复行是我们最常见的操作之一，下面就为您介绍六种适合不同情况的SQL Server删除重复行的方法，供您参考。
1.如果有ID字段，就是具有唯一性的字段
- 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来判断重复的条件，如只有col1，那么只要col1字段内容相同即表示记录相同。
2. 如果是判断所有字段也可以这样
- select * into #aa from table group by id1,id2,....
- delete table
- insert into table
- select * from #aa
3. 没有ID的情况
- 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 联合主键
- 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来判断重复的条件，如只有col1，那么只要col1字段内容相同即表示记录相同。
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
原文链接：http://www.cnblogs.com/zhangshufeng/archive/2011/09/05/2167079.html
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