Question

I have a table which contains due dates for individual member records. Each row contains four fields:

 ID     |    Next_Due    |    Next_Due_Missed    |    Amount
=============================================================
  123   |   2010-12-05   |        NULL           |    41.32
  456   |   2010-12-10   |       2010-12-05      |    21.44
  789   |   2010-12-20   |       2010-12-10      |    39.99

ID is the unique id of each MEMBER

Next Due – is the next due day of their regular subscription period

Next_Due_Missed is populated ONLY if there was an error collecting the first round of subscription payment.

Amount is amount owned for subscription.

My goal is to create a sql query that checks if next_due_missed exists and is not null. If it does, use that value as the ‘$date’. If not, set $date = value of next_due

this is done easily enough except my results are grouped by Next_Due in normal circumstances and will omit next_due_missed if I combine the way I currently am.

Every payment period, there may be 600+ records with next_due equal to the desired date (and 10-15 equal to next_due_missed).

My current query is:

$stmt = $db->prepare("SELECT next_due, next_due_missed FROM table_name WHERE (next_due > CURDATE() OR next_due_missed > CURDATE()) GROUP BY next_due ASC");

This only returns results for next_due however. Omitting the GROUP BY clause returns hundreds of results (while I need to group in this stage).

Similarly at a later point, I will need to break out those individual records and actually create payment records based on the ‘next_due’ and ‘next_due_missed’ values.

Any ideas what I am missing?

Answer 1

I am not sure the purpose of your GROUP BY other than to get DISTINCT values, but left it in in case you provided a partial query:

SELECT coalesce(next_due_missed, next_due) as EffectiveNextDue
FROM table_name 
WHERE coalesce(next_due_missed, next_due) > CURDATE()
GROUP BY coalesce(next_due_missed, next_due)