删除重复数据6种方法

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。

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

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

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。

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...)

select   distinct   *   into   #temp   from   tablename       delete   tablename       go     insert   tablename   select   *   from   #temp   Sqlclub   go     drop   table   #temp