sql性能优化

		 select  tb.MovieID
				 ,d.MovieName
				 ,tb.BoxOffice as BoxOffice
				 ,tb3.SUMBoxOffice as SUMBoxOffice
		 from (     
				  select a.MovieID,sum(a.BoxOffice) as BoxOffice
				  from MovieDayBoxOffice a 
				  where a.InsertDate>='2012-1-1' and a.InsertDate<='2013-03-20' 
				  group by a.MovieID
	           ) as tb 
			  join(
				    select a.MovieID,SUM(a.BoxOffice) as SUMBoxOffice
					from MovieDayBoxOffice a
					where a.InsertDate<='2013-03-20'
					group by MovieID
				  ) as tb3 on tb3.MovieID=tb.MovieID                
			  join BaseMovieInfo d on tb.MovieID=d.ID				  
		 order by tb.BoxOffice desc