Question

I’m learning SQL, so please bear with me. I was wondering if the following is possible, and if so, how do you reference previous selections?

SELECT [col1] as something1, [col2] as something2, 
       <Can I use something1 or something2 in the third selection?> 
  FROM [MyTable] 
 WHERE <Condition>

Answer 1

Per this answer I do not think that this will work in SQL Server.

If you really need to use the aliases you can do:

SELECT yoursubquery.something1, yoursubquery.something2, 
  FROM (
        SELECT [col1] as something1, [col2] as something2 
          FROM [MyTable]
         WHERE <Condition>
       ) yoursubquery

Or more simply just type the full column name whenever you need it:

SELECT [col1] as something1, [col2] as something2, 
       [col1] + [col2] -- or whatever else you wanted to do 
  FROM [MyTable] 
 WHERE <Condition>