存储过程有点慢,帮忙看下如何优化

create PROCEDURE dbo.bb 
@begintime datetime, 
@endtime datetime 
as 
 begin 
    while @begintime<dateadd(dd,1,@endtime) 
    begin   
         declare @a1 int,@a2 Varchar (50),@b int      
                select @b=0 
         declare aa CURSOR   
        for select GoodsID,StoreID from Fin_StoreDaily01 where RunDate=dateadd(dd,-1,@begintime)
        open aa                   
              fetch aa into @a1,@a2 
        while  @@sqlstatus<>2 
        begin 
              select @b=(select count(*) from Fin_StoreDaily01 where GoodsID=@a1 and StoreID=@a2 and RunDate=@begintime)  
             if @b=0 
             begin 
                    insert into Fin_StoreDaily01 (RunDate,GoodsID,StoreID,AcctType)  
                 select @begintime ,GoodsID,StoreID,AcctType from Fin_StoreDaily01 
                    where RunDate=dateadd(dd,-1,@begintime) and GoodsID =@a1 and StoreID=@a2 
              end 
            fetch aa into @a1,@a2 
        end 
        close aa                    
             deallocate cursor aa 
        select @begintime=dateadd(dd,1,@begintime) 
    end 
end