WITH SEATS AS (
  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
)
SELECT
  LINE_ID AS LINE,
  SEAT_NO - 2 AS SEAT_F,
  SEAT_NO AS SEAT_T
FROM
  SEATS
WHERE
  RSV_STATUS = '0'
  AND PREV_STATUS = '0'
  AND PREV2_STATUS = '0'
ORDER BY
  LINE DESC,
  SEAT_F ASC;