Multiplying two columns which have been calculated on a CASE statement

Question

I am performing a SQL query in PostgreSQL using a CASE statement like this:

SELECT
    CASE column1
        WHEN something THEN 10
        ELSE 20
          


        

Answer 1

You can always use a CTE to abstract things away to a different level, if that helps - something along the lines of ...

With CTE as
(
 SELECT
  CASE column1
    WHEN something THEN 10
    ELSE 20
    END AS newcol1,
  CASE column12
    WHEN something THEN 30
    ELSE 40
    END AS newcol2,
  column3,
 FROM table
)
SELECT
  newcol1, newcol2,
  count(column3) as newcol3,
 (newcol2 * newcol3) AS newcol4
FROM CTE 
GROUP BY newcol1,newcol2,newcol3