如果在Sql Server视图中声明

Question

如果销售日期已过期或尚未激活，但仅当assignDate为true，才想将saletype设置为0。我如何在视图中构建它？

SELECT  dbo.ItemStore.SaleType, dbo.ItemStore.SpecialBuyFromDate AS SaleStartDate , 
dbo.ItemStore.SpecialBuyToDate AS SaleEndDate , dbo.ItemStore.AssignDate 
FROM   dbo.ItemMainAndStoreView 

Answer 1

使用CASE表达

你需要允许时间方面GETDATE()因此我的DATEADD/DATEDIFF删除正确日期范围检查的时间组件。

对于SQL Server 2008+你可以使用CAST（GETDATE（）的日期）

SELECT 
    CASE 
     WHEN DATEADD(day, 0, DATEDIFF(day, 0, GETDATE())) 
       BETWEEN dbo.ItemStore.SpecialBuyFromDate AND dbo.ItemStore.SpecialBuyToDate 
      THEN dbo.ItemStore.SaleType 
      ELSE 0 
    END AS SaleType 
    dbo.ItemStore.SpecialBuyFromDate AS SaleStartDate , 
    dbo.ItemStore.SpecialBuyToDate AS SaleEndDate, 
    CASE 
FROM  
    dbo.ItemMainAndStoreView 

Answer 2

利用Case..When将解决你的问题很容易

例如：

USE AdventureWorks2008R2; 
GO 
SELECT ProductNumber, Name, 'Price Range' = 
     CASE 
     WHEN ListPrice = 0 THEN 'Mfg item - not for resale' 
     WHEN ListPrice < 50 THEN 'Under $50' 
     WHEN ListPrice >= 50 and ListPrice < 250 THEN 'Under $250' 
     WHEN ListPrice >= 250 and ListPrice < 1000 THEN 'Under $1000' 
     ELSE 'Over $1000' 
     END 
FROM Production.Product 
ORDER BY ProductNumber ; 
GO 

Answer 3

SELECT case 
    when getdate() between dbo.ItemStore.SpecialBuyFromDate 
     and dbo.ItemStore.SpecialBuyToDate 
    then dbo.ItemStore.SaleType 
    else 0 end as SaleType, 
    dbo.ItemStore.SpecialBuyFromDate AS SaleStartDate, 
    dbo.ItemStore.SpecialBuyToDate AS SaleEndDate 
FROM dbo.ItemMainAndStoreView