(CASE WHEN cl.area_id IS NOT NULL THEN
              (SELECT SUBSTR(SYS_CONNECT_BY_PATH(art.area_name,'  '),10)
                FROM area_tree art
               WHERE art.parent_id IS NULL
               START WITH art.area_id = cl.area_id
             CONNECT BY PRIOR art.parent_id = art.area_id)
           ELSE
              NULL
      END) AS area