Question

编辑：使用更好的方法解决了这个问题。而不是使用变量我连接结果以获得我想要的输出。

我试图从几个不同的表中的几个字段中获取值，并且工作正常。但我还希望有一个＆＃34; @ Description＆＃34;这是基于每行现有值的硬编码文本的串联。

DECLARE @Description VARCHAR(1000) = ''

SELECT t1.ID
      t1.myType
      t1.myName
      ,CASE WHEN 
      (
          t1.aValue1 = 1 
          AND t1.aValue2 = 1
          AND t2.aValue1 = 1
          AND t2.aValue2 = 1
      )
         THEN 'ELIGIBLE'
         ELSE 'NOT ELIGIBLE'
       END AS 'isEligible'

      ,@Description 
      -- Then I'm trying to set the description 
      /*
      IF    
          (
            t1.aValue1 = 2
          )
      SET @Description = @Description + ' t1.aValue1 is 2'
      IF
          (
            t1.aValue2 = 2
          )
      SET @Description = @Description + ' t1.aValue2 is 2'    
      IF
          (
            t2.aValue1 = 2
          )
      SET @Description = @Description + ' t2.aValue1 is 2'    
      IF
          (
            t2.aValue2 = 2
          )
      SET @Description = @Description + ' t2.aValue2 is 2'        
      */
      END AS 'Description'

  FROM [dbo].[Table1] t1
  JOIN [dbo].[Table2] t2 ON t1.ID = t2.ID

例如，如果一行有t1.aValue1 = 2且t2.aValue1 = 2，那么输出可能看起来像这样。

ID | myType | myName | isEligible | Description
-----------------------------------------------
... 
24 | Red | John | Not Eligible | t1.aValue1 is 2 t2.aValue1 is 2
25 | Blue | Eric | Eligible | 
etc...

我正在使用SSMS 2008 R2。我该如何做到这一点？

Answer 1

你有变量，但预期的结果看起来你真的想要它到行？你可以通过使用case来获取它，如下所示：

 END AS isEligible,
 case when t1.aValue1 = 2 then 't1.aValue1 is 2 ' else '' end +
 case when t1.aValue2 = 2 then 't1.aValue2 is 2 ' else '' end +
 case when t2.aValue1 = 2 then 't2.aValue1 is 2 ' else '' end +
 case when t2.aValue2 = 2 then 't2.aValue2 is 2 ' else '' end as Description

SQL IF在SELECT语句中设置参数值

1 个答案: