六种删除数据库重复行的方法

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