Recursive pl/pgsql function ...

'k, this isn't quite working as expected (or, rather, hoped) ... I've created a
recursive function (that does work nicely) that takes a date in the past, and
keeps advancing in steps of 'n months' until the date is in the future:
CREATE OR REPLACE FUNCTION get_next_billing_date(timestamp with time zone,
int4) RETURNS TIMESTAMP AS 'DECLARE  max_date RECORD;  ret TIMESTAMP WITH TIME ZONE;
  start_date ALIAS FOR $1;  payment_period ALIAS FOR $2;
BEGIN
 SELECT INTO max_date CASE WHEN now() < start_date + ( payment_period || ''
months'')::interval THEN payment_period ELSE NULL END;
 IF max_date.case IS NULL THEN   SELECT INTO ret get_next_billing_date(start_date + ( payment_period || ''
months'')::interval, payment_period); ELSE   RETURN start_date + ( payment_period || '' months'')::interval; END IF;
RETURNret;END; 
' LANGUAGE plpgsql;

It works, no problem there:

# select get_next_billing_date('2005-10-15', 3);get_next_billing_date
-----------------------2007-01-15 00:00:00
(1 row)

But, as soon as I try and use that function as a field in a query, it gives an
error:

1 Record:
# select get_next_billing_date(activated, 12) from company_details where
company_id = 771;  get_next_billing_date
----------------------------2007-05-03 15:09:19.491958
(1 row)

More then one Record:
# select get_next_billing_date(activated, 12) from company_details;
ERROR:  control reached end of function without RETURN
CONTEXT:  PL/pgSQL function "get_next_billing_date"

Something I've written wrong in the function, or just not something that is
doable?

Thanks ...

----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email . scrappy@hub.org                              MSN . scrappy@hub.org
Yahoo . yscrappy               Skype: hub.org        ICQ . 7615664