SELECT PUN.UN_NUMBER , PHC.HAZARD_CLASS FROM PO_HAZARD_CLASSES PHC , PO_UN_NUMBERS PUN WHERE SYSDATE < NVL(PHC.INACTIVE_DATE , SYSDATE+1) AND SYSDATE < NVL(PUN.INACTIVE_DATE , SYSDATE+1) AND PHC.HAZARD_CLASS_ID = PUN.HAZARD_CLASS_ID UNION SELECT PUN.UN_NUMBER , '' FROM PO_UN_NUMBERS PUN WHERE SYSDATE < NVL(PUN.INACTIVE_DATE , SYSDATE+1) AND NVL(PUN.HAZARD_CLASS_ID , -9999) = -9999