SELECT DT_Products.itemcode, DT_Products.price, DT_CustomerPrices.custitemcode, DT_CustomerPrices.custPrice, DT_CustomerPrices.Custnum, DT_Products.active
FROM DT_Products LEFT JOIN DT_CustomerPrices ON DT_Products.itemcode = DT_CustomerPrices.custitemcode
WHERE DT_CustomerPrices.Custnum='4415' AND DT_Products.active=1