六种SQL Server删除重复行的方法(转)

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  

以上就是SQL Server删除重复行的方法介绍。