Select m.MOID, a.DATE, m.NAME, a.RAR, a.ZIP
FROM (SELECT * FROM (SELECT MOID, RAR,null ZIP, DATE FROM MDA
UNION ALL
SELECT MOID, RAR,null ZIP, DATE FROM MDA2)
UNION ALL
(SELECT MOID,null RAR, ZIP, DATE FROM SAS
UNION ALL
SELECT MOID,null RAR, ZIP, DATE FROM SAS2))a
LEFT JOIN ORIGINAL m ON m.MOID = a.MOID;