Find column name SQL

Question

If it is possible, I want to return another column that contains the name of the column where the variable is found (CH1, CH2 or CH3).

Something like:

v1 => ch3

v2 => ch1

This is my query:

SELECT variable
FROM Variables , Names
WHERE (Variables.ID = Names.Ch1 or  Variables.ID = Names.Ch2 or Variables.ID = Names.Ch3 ) 

The format of my tables:

Names(#ID,Ch2,Ch2,Ch3)
Variables(#ID, variable,...)

I tried with %columName% but I get an error.

Answer 1

The correct syntax is more like:

select v.*,
       (case when v.id = n.ch1 then 'CH1'
             when v.id = n.ch2 then 'CH2'
             when v.id = n.ch3 then 'CH3'
        end) as WhichColumn
from variables v join
     names n
     on v.ID  in (n.Ch1, n.ch2, n.ch3)

In other words, you have to explicitly put in the logic for the column names.

Answer 2

try using the LIKE if the variables ID are NOT only INT number

SELECT variable
FROM Variables , Names
WHERE 
(Variables.ID like '%Names.Ch1%' 
or  Variables.ID  like '%Names.Ch2%' 
or Variables.ID like '%Names.Ch3%' )