SQL Server - Case Statement - sql

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 > 2
THEN testValue(Without Repeating it) ELSE FailValue)
END
FROM Table
A better more thorough example:
Select CASE WHEN (Foo-stuff+bar) > 2
THEN Conditional statement without >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 > 2
THEN testValue ELSE FailValue)
END
FROM Table

Answer 1

Like so
DECLARE #t INT=1
SELECT CASE
WHEN #t>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.

Answer 2

The query can be written slightly simpler, like this:
DECLARE #T INT = 2
SELECT CASE
WHEN #T < 1 THEN 'less than one'
WHEN #T = 1 THEN 'one'
ELSE 'greater than one'
END T

Answer 3

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.

Answer 4

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]