问将视图中的计算列定义为null

EN

SELECT dbo.Nop_Manufacturer.Name,
       CAST(SUM(dbo.Nop_OrderProductVariant.PriceExclTax) AS INT)           AS
       SALES,
       CAST(MONTH(dbo.Nop_Order.PaidDate) AS INT)                           AS
       paid_month,
       CAST(YEAR(dbo.Nop_Order.PaidDate) AS INT)                            AS
       paid_year,
       CAST(COUNT(dbo.Nop_OrderProductVariant.OrderProductVariantID) AS INT)AS
       num_prod_sold
FROM   dbo.Nop_ProductVariant
       INNER JOIN dbo.Nop_OrderProductVariant
         ON dbo.Nop_ProductVariant.ProductVariantId =
            dbo.Nop_OrderProductVariant.ProductVariantID
       INNER JOIN dbo.Nop_Product
         ON dbo.Nop_ProductVariant.ProductID = dbo.Nop_Product.ProductId
       INNER JOIN dbo.Nop_Product_Manufacturer_Mapping
                  INNER JOIN dbo.Nop_Manufacturer
                    ON dbo.Nop_Product_Manufacturer_Mapping.ManufacturerID =
                       dbo.Nop_Manufacturer.ManufacturerID
         ON dbo.Nop_Product.ProductId =
            dbo.Nop_Product_Manufacturer_Mapping.ProductID
       INNER JOIN dbo.Nop_Order
         ON dbo.Nop_OrderProductVariant.OrderID = dbo.Nop_Order.OrderID
WHERE  ( NOT ( dbo.Nop_Order.PaidDate IS NULL ) )
GROUP  BY dbo.Nop_Manufacturer.Name,
          MONTH(dbo.Nop_Order.PaidDate),
          YEAR(dbo.Nop_Order.PaidDate)