Question

My issue is fairly simple to explain:

I need a query which selects the DISTINCT for a column, but I need to select other columns too, normally without DISTINCT. Can anyone show me such a query as an example?

It should be an universal query!

Thanks.

$sql = 'SELECT DISTINCT user_id FROM ' . DONATION_SECURITY_TABLE . " 
        $sql_where 
        ORDER BY payment_status ASC, user_id ASC";

I need to make this query select other stuff too, not just user_id distinct, I also need to select: donation_id, payment_status, pending_reason, txn_id, mc_gross and amount.

Sample table:

donation_id    user_id    mc_gross    payment_status    txn_id (has UNIQUE index)
1              4          5.00        Completed         g54g4
2              5          10.00       Pending           54yhh
3              4          6.00        Pending           54yhg
4              7          15.00       Completed         fdhgf

The query should return:
DISTINCT for user_id, SUM of mc_gross for the distinct-ed user_id, latest payment_status (would return Pending for user_id = 4).

Answer 1

This should work:

select t1.user_id, 
       t1.donation_id, 
       t1.payment_status, 
       t1.pending_reason,
       t1.txn_id, 
       t2.sum_gross, 
       t1.amount
from the_table t1
join (
   select max(donation_id) as max_id, 
          sum(mc_gross) as sum_gross,
          user_id
   from the_table
   group by user_id
) t2 on t2.max_id = t1.donation_id
    and t2.user_id = t1.user_id;