SELECT id,grp_id,in_str,w
  FROM (SELECT t.*,rank() OVER(PARTITION BY grp_id ORDER BY LENGTH(w) DESC) rnk
          FROM (SELECT t.*,COUNT(DISTINCT id) OVER(PARTITION BY grp_id,w) cnt_w
                  FROM (SELECT t.*,REPLACE(SYS_CONNECT_BY_PATH(c,’/'),’/') w
                         FROM (SELECT *
                                 FROM (SELECT t.*,COUNT(DISTINCT id) OVER(PARTITION BY grp_id,c) cnt_c
                                         FROM (SELECT t.*,rn,SUBSTR(in_str,rn,1) c
                                                FROM (SELECT t8.*,COUNT(*) OVER (PARTITION BY grp_id) cnt FROM t8) t
                                                    ,(SELECT ROWNUM rn FROM DUAL CONNECT BY ROWNUM<=100)
                                              ) t
                                       WHERE c IS NOT NULL
                                       )
                               WHERE cnt=cnt_c
                               ) t
                       CONNECT BY id=PRIOR id AND rn = PRIOR rn +1
                       ) t
                ) t
        WHERE cnt = cnt_w
        )
WHERE rnk=1;