Question

I’m confused about this:

SELECT request_id, SUM( cc_amount ) AS amt,
       DATE_FORMAT( transaction_datetime,  '%b %y' ) AS tdate
  FROM ee_request_cc
 GROUP BY DATE_FORMAT( transaction_datetime,  '%b %y' ) 

UNION 

SELECT request_id, SUM( request_amount ) AS amt,
       DATE_FORMAT( transaction_date,  '%b %y' ) AS tdate
  FROM ee_request_paypal
 GROUP BY DATE_FORMAT( transaction_date,  '%b %y' )

I’m getting:

id    amt    tdate
20  86.00   Mar 12
80   5.00   Apr 12
23  55.00   Mar 12

Whereas I want to add all amounts for March and April like:

id     amt   tdate
20  141.00  Mar 12
80    5.00  Apr 12

Please suggest me the change in my query.

Answer 1

You need to get all the results, and then perform the aggregation:

SELECT table_both.request_id, table_both.tdate, SUM(table_both.amount) AS amt
FROM (SELECT request_id, cc_amount AS amt, DATE_FORMAT(transaction_datetime,'%b %y') AS tdate
    FROM table1 

    UNION ALL --Don't remove the duplicates

    SELECT request_id, request_amount, DATE_FORMAT(transaction_date,'%b %y')
    FROM table2) table_both
GROUP BY table_both.request_id, table_both.tdate --You don't need to add the format function in the group by