1.如果有ID字段,就是具有唯一性的字段 复制代码 代码如下: 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 复制代码 代码如下: select * into #aa from table group by id1,id2,.... delete table insert into table select * from #aa
3. 没有ID的情况 复制代码 代码如下: 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 复制代码 代码如下: 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. 复制代码 代码如下: 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. 复制代码 代码如下: select distinct * into #temp from tablename delete tablename go insert tablename select * from #temp Sqlclub go drop table #temp