[转]六种删除数据库重复行的方法

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

1. delect table where id not in (
2. 
   
3. select max(id) from table group by col1,col2,col3...
4. )

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

1. select * into #aa from table group by id1,id2,....
2. delete table
3. insert into table
4. select * from #aa

3. 没有ID的情况

1. select identity(int,1,1) as id,* into #temp from tabel
2. delect # where id not in (
3. select max(id) from # group by col1,col2,col3...)
4. delect table
5. inset into table(...)
6. select ..... from #temp

4. col1+','+col2+','...col5 联合主键

1. select * from table where col1+','+col2+','...col5 in (
2. select max(col1+','+col2+','...col5) from table
3. where having count(*)>1
4. group by col1,col2,col3,col4
5. )

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.

1. select identity(int,1,1) as id,* into #temp from tabel
2. select * from #temp where id in (
3. select max(id) from #emp where having count(*)>1 group by col1,col2,col3...)

6.

1. select distinct * into #temp from tablename
2. delete tablename
3. go
4. insert tablename select * from #temp Sqlclub
5. go
6. drop table #temp

以上就是SQL Server删除重复行的方法介绍。