Ich habe zwei MySQL-Tabellen:

table: loan
--------------------------------------------------------
 id | advance_id | loan_amount | deposit_amount | date
--------------------------------------------------------
 1 | 22556678 | 5000 | 0 | 2015-02-06
 2 | 22556678 | 5000 | 0 | 2015-02-07
--------------------------------------------------------

table: advance
--------------------------------------------------------
id | advance_id | advance_amount | purpose | date
--------------------------------------------------------
 1 | 22556678 | 20000 | purchase | 2015-01-30
 2 | 22556678 | 10000 | purchase | 2015-01-31

Ich möchte die Summe von 'loan_amount' aus der Tabelle: loan und die Summe von 'advance_amount' aus der Tabelle: advance in einer von INNER JOIN verknüpften mysql-Abfrage erhalten.

Wie erhält man die Summe aus den Spalten zweier Tabellen?

SELECT 
  a.advance_id,
  SUM(a.advance_amount) AS adv_amount,
  a.purpose,
  a.date,
  SUM(l.loan_amount) AS loan_amount 
FROM
  advance AS a 
  INNER JOIN loan AS l 
    ON a.advance_id = l.advance_id 
GROUP BY a.advance_id 
HAVING SUM(l.loan_amount) - SUM(l.deposit_amount) > 0