CALL sa_ansi_standard_packages( 'SQL:2003', 
'SELECT * 
   FROM ( SELECT o.SalesRepresentative, 
   o.Region, 
                 SUM( s.Quantity * p.UnitPrice ) AS total_sales,
                 DENSE_RANK() OVER ( PARTITION BY o.Region, 
                                     GROUPING( o.SalesRepresentative ) 
                                     ORDER BY total_sales DESC ) AS sales_rank
            FROM Product p, SalesOrderItems s, SalesOrders o
            WHERE p.ID = s.ProductID AND s.ID = o.ID
            GROUP BY GROUPING SETS( ( o.SalesRepresentative, o.Region ), o.Region ) ) AS DT 
   WHERE sales_rank <= 3
   ORDER BY Region, sales_rank');