Павел Ерошевич

select *
  from (select t.MOID, m.DDATE, m.RAR, null ZIP
          from Original t,
               (select * from MDA m1 UNION select * from MDA2 m2) m
         where m.MOID = t.MOID
        UNION ALL
        select t.MOID, s.DDATE, null RAR, s.ZIP ZIP
          from Original t,
               (select * from SAS s1 UNION select * from SAS2 s2) s
         where s.MOID = t.MOID)
 ORDER BY MOID