Link to MySQL alias aggregate column

Question

Following my summarizing-two-conditions-on-the-same-sql-table question, I added a RATIO column, which is just one SUM (...) column divided by a second SUM (...):

SELECT
    COMPANY_ID,
    SUM(CASE WHEN STATUS IN (0, 1) THEN 1 ELSE 0 END) AS NON_BILLABLE,
    SUM(CASE WHEN STATUS IN (2, 3) THEN 1 ELSE 0 END) AS BILLABLE
    SUM(NON_BILLABLE)/SUM(BILLABLE) AS RATIO
FROM TRANSACTIONS
GROUP BY COMPANY_ID

It looks nice and clean to define a RATIO like this, but SQL is also apparently forbidden .

To make the query work, I simply copied the CASE statements for NON_BILLABLE and BILLABLE.

SELECT
    COMPANY_ID,
    SUM(CASE WHEN STATUS IN (0, 1) THEN 1 ELSE 0 END) AS NON_BILLABLE,
    SUM(CASE WHEN STATUS IN (2, 3) THEN 1 ELSE 0 END) AS BILLABLE
    SUM(CASE WHEN STATUS IN (0, 1) THEN 1 ELSE 0 END)/SUM(CASE WHEN STATUS IN (2, 3) THEN 1 ELSE 0 END) AS RATIO
FROM TRANSACTIONS
GROUP BY COMPANY_ID

Is there a better, cleaner (not redundant) way to write this query?

Answer 1

Using:

SELECT x.company_id,
       x.non_billable,
       x.billable,
       x.non_billable/x.billable AS RATIO
  FROM (SELECT t.company_id
              SUM(CASE WHEN STATUS IN (0, 1) THEN 1 ELSE 0 END) AS NON_BILLABLE,
              SUM(CASE WHEN STATUS IN (2, 3) THEN 1 ELSE 0 END) AS BILLABLE
         FROM TRANSACTIONS
     GROUP BY t.company_id) x