测试查询语句

 

declare   @t   table   
  (   
  tid   int,   
  tv   char(1)   
  )   
  insert   into   @t   
  select   1,'a'   union   all
   select   1,'a'   union   all
  select   2,'b'   union   all   
  select   3,'m'   union   all   
  select   4,'b'   union   all   
  select   5,'c'   union   all   
  select   6,'m'   union   all   
  select   7,'v'   union   all   
  select   8,'m'   union   all   
  select   9,'n'   
    
  select   distinct *,(select   count(1)   from   @t   where   tid<=t.tid   and   tv=t.tv)   c   
  from   @t   t