SELECT
  LINE_ID AS LINE,
  SEAT_NO-2 AS SEAT_F,
  SEAT_NO AS SEAT_T
FROM (
  SELECT
    LINE_ID,
    SEAT_NO,
    RSV_STATUS,
    LAG(RSV_STATUS, 1) OVER(PARTITION BY LINE_ID ORDER BY SEAT_NO) AS PREV_STATUS,
    LAG(RSV_STATUS, 2) OVER(PARTITION BY LINE_ID ORDER BY SEAT_NO) AS PREV2_STATUS
  FROM SEAT_RESERVE
) AS T
WHERE RSV_STATUS = '0' AND PREV_STATUS = '0' AND PREV2_STATUS = '0'
ORDER BY LINE DESC, SEAT_F ASC;