Row_Number() 分組排序

  SELECT  a.id 
         ,a.cnname
         ,b.personid                  
         ,Row_number() OVER(partition BY personid ORDER BY releasetime DESC) num
         ,releasetime                
  from   ent_movie a  
         LEFT JOIN ent_movie_relate_person b ON a.id = b.movieid 	   				                             
  WHERE  a.typeid=1 and a.cnName is not null and a.cnName!='' 
         AND b.professionid = 1
         and a.releaseTime>=DATEADD(YY,-3,GETDATE()) and  a.releaseTime<=GETDATE()

語法形式：ROW_NUMBER() OVER(PARTITION BY COL1 ORDER BY COL2) 

解釋：根據COL1分組，在分組內部根據 COL2排序，而此函數計算的值就表示每組內部排序後的順序編號（組內連續的唯一的) 

參考學習：http://www.jb51.net/article/29162.htm