[Oracle/오라클] LEAD() 다음 레코드 값, LAG() 이전 레코드 값 조회

LEAD(필드명) OVER (PARTITION BY 그룹필드명 ORDER BY 정렬필드 명) 

★ ORDER BY 필수

SELECT TRAIN_NO, RUN_ORDR, STATION_NM,

NVL(LEAD(STATION_NM) OVER(PARTITION BY TRAIN_NO ORDER BY RUN_ORDR),' ') NEXT_STATION

FROM TB_TRAIN_TM;

 

LAG(필드명) OVER (PARTITION BY 그룹필드명 ORDER BY 정렬필드 명) 

SELECT TRAIN_NO, RUN_ORDR, STATION_NM,

NVL(LAG(STATION_NM) OVER(PARTITION BY TRAIN_NO ORDER BY RUN_ORDR),' ') PREV_STATION

FROM TB_TRAIN_TM;