WITH consecutive_seats AS (
    SELECT
        LINE_ID,
        SEAT_NO,
        LAG(SEAT_NO, 1) OVER (PARTITION BY LINE_ID ORDER BY SEAT_NO) AS prev_seat,
        LEAD(SEAT_NO, 1) OVER (PARTITION BY LINE_ID ORDER BY SEAT_NO) AS next_seat
    FROM
        SEAT_RESERVE
    WHERE
        RSV_STATUS = '0'
),
triples AS (
    SELECT
        LINE_ID,
        SEAT_NO AS SEAT_F,
        LEAD(SEAT_NO, 2) OVER (PARTITION BY LINE_ID ORDER BY SEAT_NO) AS SEAT_T
    FROM
        consecutive_seats
    WHERE
        prev_seat = SEAT_NO - 1 AND next_seat = SEAT_NO + 1
)
SELECT
    LINE_ID AS LINE,
    SEAT_F,
    SEAT_T
FROM
    triples
WHERE
    SEAT_T IS NOT NULL
ORDER BY
    LINE_ID DESC,
    SEAT_F ASC;