/*Each data set must be sorted by ProdCode before mergining*/

proc sort data=prog2.prices out=pricesort;
   by ProdCode;
run;

proc sort data=prog2.todaysales out=salesort;
   by ProdCode;
run;

data revenue
   NotSold(keep=Price ProdCode)
   InValidCode(Keep=ProdCode Qty);
   merge PriceSort(in=InPrice) SaleSort(in=InSales);
   by ProdCode;
   if InPrice and InSales then do; /*Matching Prodcodes*/
      Revenue=Qty*Price; /*Only necessary to 
                          calculte revenue for matches*/
      output revenue;
   end;
     else if InPrice and not InSales then output notsold;
         /*Product not in TodaySales Data set. */
         /*It has not sold this week*/
     else if InSales and not InPrice then output invalidcode;
            /*Product in TodaySales that is not 
              in the master price list.*/
run;

proc print data=revenue;
run;

proc print data=notsold;
run;

proc print data=invalidcode;
run;