Angular read component name from json and add 'this' to the name

Example:

SELECT
   (SELECT SUM(...) FROM ...) as turnover,
   (SELECT SUM(...) FROM ...) as cost,
   turnover - cost as profit

Sure this is invalid (at least in Postgres) but how to achieve the same in a query without rewriting the sub-query twice?

Solution 1:

Like so:

SELECT
   turnover,
   cost,
   turnover - cost as profit
from (
   (SELECT SUM(...) FROM ...) as turnover,
   (SELECT SUM(...) FROM ...) as cost
   ) as partial_sums

Solution 2:

You could reuse the query like this:

WITH 
  TURNOVER AS (
    SELECT SUM(...) FROM ...)
  ),
  COST AS(
    SELECT SUM(...) FROM ...
  )

SELECT *
FROM(
 SELECT
   TURNOVER.sum as SUM_TURNOVER
 FROM
 TURNOVER,COST
 WHERE ....
) AS a

This is equivalent to :

SELECT *
FROM(
 SELECT
   TURNOVER.sum as SUM_TURNOVER
 FROM
 (
   SELECT SUM(...) FROM ...)
 )AS TURNOVER,
 (
   SELECT SUM(...) FROM ...
 )AS COST
 WHERE ....
) AS a

There is a point to note here. The first method is more readable and reusable, but the second method might be faster, because the DB might choose a better plan for it.