CREATE CURSOR Parts (partno C(2), YYYYMM n(6), YYYYMMprev N(6)) ... Insert records here for the last 12 periods (month) INSERT VALUES (200412, 200411) ... INSERT VALUES (200401, 200312) SELECT pn.partno, MAX(cp.YYYYMM) ; FROM Parts pn ; JOIN crsPeriods cp ON cp.YYYYMMprev = pn.YYYYMM ; LEFT JOIN Parts pn2 ON pn.partno = pn2.partno ; AND cp.YYYYMM = pn2.YYYYMM ; WHERE pn2.partno IS NULL ; GROUP BY pn.partnoYou can also follow Hilmar's suggestions.