sql - 我认为列计算中的逻辑错误

Question

我正在尝试根据在Payment桌子上完成的付款创建发票视图。视图上的字段是和字段Balance之间的差异。当我插入付款表余额字段时显示为空。 AmountDueAmountPaid

 CREATE TABLE [dbo].[payment](
[AmountDue] [money] NULL,
[AmountPaid] [money] NULL,
[Balance] [money] NULL,
[CheckNumber] [varchar](50) NULL
) ON [PRIMARY]    

我的观点：

CREATE VIEW [dbo].[invoice]
AS
SELECT     AmountDue, AmountPaid, Balance AS [[AmountPaid-AmountDue]] AS Bal],   CheckNumber
FROM         dbo.payment

去

Answer 1

你的语法不正确。现在，您正在返回Balance字段名称为（字面意思）的字段值"[AmountPaid-AmountDue]] AS Bal"

我想你想要：

CREATE VIEW [dbo].[invoice]
AS
SELECT     AmountDue, AmountPaid, AmountPaid-AmountDue AS Balance, CheckNumber
FROM         dbo.payment

虽然不清楚Balance物理Payment表上的字段应该如何应用，因为它在视图中被忽略了。