如何在sql server中将case值设置为变量？ [英] How to set case values to a variable in sql server?

问题描述

代码是：

  SELECT   CASE   WHEN  Cong> = BJP  AND  Cong> = AAP 那么 Cong 
  WHEN  BJP> = AAP 那么 BJP 
  ELSE  AAP 
  END   AS   maxvote ，Winner  AS  [参与者名称]  FROM  TableName 

我想在变量中使用maxvote别名的地方，因为我想根据这个变量过滤另一个数据。

解决方案

你真的不能这样做 - 因为SELECT没有直接替换将返回多个价值，因此值得表 - 这使得过滤有趣！



你可以选择进入一个临时表，如果这是你想要做的？

 声明  @ temptable   table  
（
 var1  int  
 
）
 
 
 插入 进入  @temptable  选择（ CASE   WHEN  n_cong> = n_bjp  AND  n_cong> = n_aap 那么 n_cong 
  WHEN  n_bjp> = n_aap 那么 n_bjp 
  ELSE  n_aap 
  END ） -  n_winby  AS  againstpartyvote 
 
  FROM  m_assembly_election1993  order   by  n_winby  desc  
 
 选择 var1 来自  @不是Temptable  

Code is :

SELECT CASE WHEN Cong >= BJP AND Cong >= AAP THEN Cong
                   WHEN BJP >= AAP THEN BJP
                   ELSE AAP
           END AS maxvote, Winner AS [Party Name] FROM TableName

I wanna use a variable in place of maxvote alias, Because I want to filter another data based on this variable.

解决方案

You can't really do that - there is no direct replacement because the SELECT will return multiple values and thus a table worth - which makes it "interesting" to filter on!

You can SELECT into a temporary table, if that's what you are trying to do?

declare @temptable table
(
var1 int

)


insert into @temptable select (CASE WHEN n_cong >= n_bjp AND n_cong >= n_aap THEN n_cong
                   WHEN n_bjp >= n_aap THEN n_bjp
                   ELSE n_aap
           END)-n_winby AS againstpartyvote

            FROM m_assembly_election1993 order by n_winby desc

            select var1 from @temptable

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