SELECT a.mps_id, b.MONTH
  FROM (SELECT   mps_id
            FROM smicscmadm.scm_mps_mast
           WHERE del_flag = 'N' AND TYPE = 'MPS' AND ROWNUM <= 6
        ORDER BY mps_id DESC) a,
       (SELECT mps_id, YEAR || MONTH AS MONTH
          FROM scm_mps_qty) b
 WHERE a.mps_id = b.mps_id

SELECT DISTINCT a.mps_id, b.MONTH
           FROM (SELECT   mps_id
                     FROM smicscmadm.scm_mps_mast
                    WHERE del_flag = 'N' AND TYPE = 'MPS' AND ROWNUM <= 6
                 ORDER BY mps_id DESC) a,
                (SELECT mps_id, YEAR || MONTH AS MONTH
                   FROM scm_mps_qty) b
          WHERE a.mps_id = b.mps_id

SELECT A.MPS_ID, B.MONTH
  FROM (SELECT MPS_ID
          FROM (SELECT MPS_ID
                  FROM SMICSCMADM.SCM_MPS_MAST
                 WHERE DEL_FLAG = 'N'
                   AND TYPE = 'MPS'
                 ORDER BY MPS_ID DESC)
         WHERE ROWNUM <= 6) A,
       (SELECT MPS_ID, YEAR || MONTH AS MONTH FROM SCM_MPS_QTY) B
 WHERE A.MPS_ID = B.MPS_ID;