在case case语句中返回列名，但没有涉及表

您好任何人都可以帮助解决以下问题，我有一个取决于月份和日期的存储过程取决于返回哪个图像。当数据在表格中时，我发现了很多关于如何解决这个问题的例子，但是我没有解决这个问题。在case case语句中返回列名，但没有涉及表

我之所以这样做是因为在程序中修改sql比改变和上传新代码到网站更容易。

DECLARE @CurrentMonth int 
SET @CurrentMonth = (MONTH(GETDATE())) 

DECLARE @CurrentDate int 
SET @CurrentDate = (Day(GETDATE())) 

--DECLARE @Url varchar(100) 
--SET @URL = '' 


    SET NOCOUNT ON; 

    SELECT 
      --Set image for xmas 
      CASE WHEN @CurrentMonth = 12 AND @CurrentDate = 25 
      THEN (SELECT 'imagetest.png' AS URL) 
      --Set for easter 
      WHEN @CurrentMonth = 3 AND @CurrentDate = 19 
      THEN (SELECT 'imagetest2.png' AS url) 
      --Keep setting images for events 
      WHEN @CurrentMonth = 3 AND @CurrentDate = 19 
      THEN (SELECT 'imagetest3.png' AS url) 
      --If no match, return default image 
      ELSE (SELECT 'logo.png' AS url) 
     END 

     -- return @URL 
    END

sp执行正常，但当我想要url是列名时，列是（无列名）。

任何有经验的人的帮助将不胜感激。

我使用SQL2008R2

来源

2014-02-20 George Phillipson

你不需要内SELECT S：

SELECT 
     --Set image for xmas 
     CASE WHEN @CurrentMonth = 12 AND @CurrentDate = 25 
     THEN 'imagetest.png' 
     --Set for easter 
     WHEN @CurrentMonth = 3 AND @CurrentDate = 19 
     THEN 'imagetest2.png' 
     --Keep setting images for events 
     WHEN @CurrentMonth = 3 AND @CurrentDate = 19 
     THEN 'imagetest3.png' 
     --If no match, return default image 
     ELSE 'logo.png' 
    END AS url

BTW，3月19日绝不会是一个复活节。 3月22日是最早可能的Easter date

来源

2014-02-20 23:34:17

嗨D斯坦利我知道，我只是把任何日期，以检查它是否有效:) –

D斯坦利我需要等待3分钟才能授予答案，有趣的是，当你看到答案时看起来如此简单，当时我是ra my着我的大脑，试图弄明白这一点 –

向case语句添加列别名。 Case语句是if/then命题，SQL Server不会根据测试的列分配名称。你可以自由地命名它们。

DECLARE @CurrentMonth int 
SET @CurrentMonth = (MONTH(GETDATE())) 

DECLARE @CurrentDate int 
SET @CurrentDate = (Day(GETDATE())) 

--DECLARE @Url varchar(100) 
--SET @URL = '' 


SET NOCOUNT ON; 

SELECT 
     --Set image for xmas 
     CASE WHEN @CurrentMonth = 12 AND @CurrentDate = 25 
     THEN (SELECT 'imagetest.png' AS URL) 
     --Set for easter 
     WHEN @CurrentMonth = 3 AND @CurrentDate = 19 
     THEN (SELECT 'imagetest2.png' AS url) 
     --Keep setting images for events 
     WHEN @CurrentMonth = 3 AND @CurrentDate = 19 
     THEN (SELECT 'imagetest3.png' AS url) 
     --If no match, return default image 
     ELSE (SELECT 'logo.png' AS url) 
    END as MyURL --edit to your liking 

    -- return @URL 
END

来源

2014-02-20 23:35:00 wruckie

的AS URL需要在你的case语句

CASE 
... 
END AS URL

来源

2014-02-20 23:35:05

结束你的case语句后添加您的列名：

SELECT 
    --Set image for xmas 
     CASE WHEN @CurrentMonth = 12 AND @CurrentDate = 25 
     THEN (SELECT 'imagetest.png' AS URL) 
     --Set for easter 
     WHEN @CurrentMonth = 3 AND @CurrentDate = 19 
     THEN (SELECT 'imagetest2.png' AS url) 
     --Keep setting images for events 
     WHEN @CurrentMonth = 3 AND @CurrentDate = 19 
     THEN (SELECT 'imagetest3.png' AS url) 
     --If no match, return default image 
     ELSE (SELECT 'logo.png' AS url) 
    END AS url

来源

2014-02-20 23:41:49 cdev

这是一个不同的方式，你可以这样做可能更容易维护：

select top 1 Url from (
    select Mon = null, Dat = null, Url = 'logo.png' union all 
    select 12, 25, 'imagetest.png' union all 
    select 3, 19, 'imagetest2.png' union all 
    select 3, 19, 'imagetest3.png' 
) x 
where (Mon = @CurrentMonth and Dat = @CurrentDate) or (Mon is null) 
order by Mon desc

来源

2014-02-20 23:49:29 Guffa

在case case语句中返回列名，但没有涉及表

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