WITH SeatAvailability AS (
    SELECT
        LINE_ID,
        SEAT_NO,
        LEAD(SEAT_NO, 2) OVER(PARTITION BY LINE_ID ORDER BY SEAT_NO) AS SEAT_T
    FROM
        SEAT_RESERVE
    WHERE
        RSV_STATUS = '0'
)
SELECT
    LINE_ID AS "LINE",
    SEAT_NO AS "SEAT_F",
    SEAT_T AS "SEAT_T"
FROM
    SeatAvailability
WHERE
    SEAT_T IS NOT NULL
ORDER BY
    LINE_ID DESC,
    SEAT_NO ASC;