I'm not sure I'm following. But, maybe this will help you:-- Set up sample dataDECLARE @ShoppingCart TABLE (ProductID INT, Quantity INT)DECLARE @Products TABLE (ProductID INT, UnitPrice_retail MONEY, SalePrice MONEY, OnSale BIT)INSERT @ShoppingCartSELECT 1, 5UNION ALL SELECT 2, 10UNION ALL SELECT 3, 7INSERT @ProductsSELECT 1, $5.00, $4.00, 1UNION ALL SELECT 2, $8.00, $4.00, 0UNION ALL SELECT 3, $99.99, $80.00, 1-- Run SelectSELECT SUM ( CASE WHEN p.onSale = 0 THEN COALESCE(p.UnitPrice_retail * s.Quantity, 0) WHEN p.onSale = 1 THEN COALESCE(p.SalePrice * s.Quantity, 0) ELSE 0 END ) AS TotalAmountFROM @ShoppingCart s INNER JOIN @Products pON s.ProductID = p.ProductID