從具有相同列的不同列的存儲過程中獲取 DateDiff

Question

首先你好，我管理一家書店，我想顯示我的書與出版日期和出版刪除日期。 我想顯示這兩天之間的日子。 例如這是我的存儲過程：

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

ALTER PROCEDURE  [dbo].[spLibrary]
AS
BEGIN 
    DECLARE @Tax int, @forwardDate DATETIME

    SET @Tax = 100
    SET @forwardDate = 7

    SELECT 
        b.BookName BookName,
        b.BookAuthor BookAuthor,
        b.BookPrice PriceWithoutTax,
        b.BookPrice + @Tax PriceWithTax,
        b.BookDate PublisDate,
        b.BookDate +  @forwardDate PublishRemoveDate
    FROM
        Book b
END

我想看看 PublishDate 和 PublisRemoveDate 之間的區別。 我嘗試但它說多標識符錯誤。 你能幫我么。 從現在開始非常感謝！

Answer 1

您可以在 SP 中向 select 添加新字段

GO
alter PROCEDURE  [dbo].[spLibrary]
AS
BEGIN 
declare @Tax int, @forwardDate DATETIME
set @Tax = 100
set @forwardDate = 7

SELECT 
b.BookName BookName,
b.BookAuthor BookAuthor,
b.BookPrice PriceWithoutTax,
b.BookPrice + @Tax  PriceWithTax,
b.BookDate PublisDate,
b.BookDate +  @forwardDate PublishRemoveDate,
datediff(day, BookDate, b.BookDate +  @forwardDate)  as DiffDays 

from 
Book b
END

Answer 2

我懷疑您想將@forwardDate天數添加到BookDate 。 如果是這樣，您應該將變量聲明為int ，然后使用dateadd() ：

dateadd(day, @forwarDate, BookDate) as PublishRemoveDate

另一方面，如果您想要日期bookDate和PublishRemoveDate之間的日期差異，請使用datediff() ：

datediff(day, BookDate, PublishRemoveDate) as diff