UPDATE (SELECT TT.MEM_NUM MN1, M.MEM_NUM MN2
          FROM SIEBEL.S_LOY_MEMBER M
               INNER JOIN SIEBEL_PURGE.TEMP_TXN_10212015 TT
                  ON M.ROW_ID = TT.MEMBER_ID)
   SET MN1 = MN2;

COMMIT;
