Question

I am struggling to work out the correct MySQL syntax to add the result of two queries. The queries draw call records from a table, both generate a single figure result, I need to add them together. I’m sure this can be done with a subquery but I can’t seem to get the syntax right.

Here are the queries:

SELECT SUM(costres) - SUM(costadmin)
FROM call_history, client
WHERE MONTH(start) = 3 AND YEAR(start) = 2012
  AND call_history.client_reseller_id = client.id
  AND client.charging_identifier <> 100000
  AND client.charging_identifier <> 999999;

SELECT SUM(costcl) - SUM(costadmin)
FROM call_history, client
WHERE MONTH(start) = 3 AND YEAR(start) = 2012
 AND call_history.client_reseller_id = client.id
 AND client.charging_identifier = 100000
 AND client.charging_identifier <> 999999;

As I said, I know this is simple, but I just can’t seem to get my head around subquery syntax in MySQL!

Thanks in advance

George

Answer 1

How about –

SELECT
    (SUM(IF(client.charging_identifier = 100000, costcl, 0)) - SUM(IF(client.charging_identifier = 100000, costadmin, 0))) +
    (SUM(IF(client.charging_identifier <> 100000, costres, 0)) - SUM(IF(client.charging_identifier <> 100000, costadmin, 0)))
FROM call_history, client
WHERE MONTH(start) = 3 AND YEAR(start) = 2012
AND call_history.client_reseller_id = client.id
AND client.charging_identifier <> 999999;