SQL Server 2005触发器不能正常工作

Question

我有一个名为order_details的表和另一个表book_inventory。

如果有时我quantity_ordered在order_details它应该从从quantity_in_stock减少该值。

这里是我的代码：

create TRIGGER [dbo].[book] 
    ON [dbo].[order_details] 
    AFTER UPDATE 
AS 

IF UPDATE(quantity_ordered) 
    UPDATE book_inventory 
    SET book_inventory.quantity_in_stock = book_inventory.quantity_in_stock - order_details.quantity_ordered 
    FROM order_details 
    WHERE book_inventory.isbn = order_details.isbn 

Answer 1

好吧，seemes对我说，写这个查询的正确方法是将

create TRIGGER [dbo].[book] 
    ON [dbo].[order_details] 
    AFTER UPDATE 
AS 

IF UPDATE(quantity_ordered) 
    UPDATE book_inventory 
    SET book_inventory.quantity_in_stock = book_inventory.quantity_in_stock - i.quantity_ordered + d.quantity_ordered 
    FROM INSERTED i 
    JOIN DELETED d 
     ON d.isbn = i.isbn 
    WHERE book_inventory.isbn = i.isbn