LAG()/LEAD() - 이전/다음 레코드 알아오기

SELECT OID, 
            LAG(OID) OVER (ORDER BY OID) NEXT_OID,
            LEAD(OID) OVER (ORDER BY OID) PREV_OID,
            ART_LEVEL, ART_TITLE
  FROM HANA_ARTICLE 
WHERE BBS_CODE='bbs10'
    AND BBS_TYPE=2
ORDER BY ART_REF DESC, ART_STEP