SELECT p.ProductName,COALESCE(bp.Quantity,0) AS BookedQty, p.Quantity - COALESCE(bp.Quantity,0) AS RemainingStock
FROM Product p
LEFT JOIN ( SELECT ProductID,SUM(Quantity) AS TotalQty
            FROM BookedProduct bp1
            INNER JOIN BookingDetails bd
            ON bd.CustomerID = bp1.CustomerID
            WHERE @Date >= bd.DateFrom AND @Date < bd.DateTo +1           
            GROUP BY ProductID
         )bp
ON bp.ProductID = p.ProductID