SQL Server - Case Statement

Question

I m almost certain you cannot do this within the context of the case statement  and I haven t been able to find any documentation about it  but is it possible to do the following   SELECT CASE WHEN testValue  gt  2  THEN testValue Without Repeating it  ELSE FailValue  END  FROM Table    A better more thorough example   Select CASE WHEN  Foo-stuff bar   gt  2  THEN Conditional statement without  gt 2 Else  Fail  END  FROM TABLE   I am looking for a way to create a select without repeating the conditional query   EDIT  Due to a poor example on my part  and the lack of answers I was looking for   testValue    Table A   Table B    Table C Table D  SELECT CASE WHEN testValue  gt  2  THEN testValue ELSE FailValue  END  FROM Table

User · Answer

I am looking for a way to create a select without repeating the conditional query.

I'm assuming that you don't want to repeat Foo-stuff+bar. You could put your calculation into a derived table:

SELECT CASE WHEN a.TestValue > 2 THEN a.TestValue ELSE 'Fail' END 
FROM (SELECT (Foo-stuff+bar) AS TestValue FROM MyTable) AS a

A common table expression would work just as well:

WITH a AS (SELECT (Foo-stuff+bar) AS TestValue FROM MyTable)
SELECT CASE WHEN a.TestValue > 2 THEN a.TestValue ELSE 'Fail' END    
FROM a

Also, each part of your switch should return the same datatype, so you may have to cast one or more cases.

User · Answer

The query can be written slightly simpler  like this   DECLARE  T INT   2   SELECT CASE           WHEN  T  lt  1 THEN  less than one            WHEN  T   1 THEN  one            ELSE  greater than one          END T

User · Answer

We can use case statement Like this  select Name EmailId gender case  when gender  M  then  F  when gender  F  then  M  end  from  dbo   Employees    WE can also it as follow   select Name EmailId case gender when  M  then  F  when  F  then  M  end  from  dbo   Employees

User · Answer

Like so  DECLARE  t INT 1  SELECT CASE             WHEN  t gt 0 THEN                 CASE                     WHEN  t 1 THEN  one                      ELSE  not one                  END             ELSE  less than one          END   EDIT  After looking more at the question  I think the best option is to create a function that calculates the value  That way  if you end up having multiple places where the calculation needs done  you only have one point to maintain the logic

[sql] SQL Server - Case Statement

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