WITH RESERVER_CHECK AS (
    SELECT
        LINE_ID AS LINE,
        SEAT_NO,
        SEAT_NO - ROW_NUMBER() OVER (ORDER BY SEAT_NO) AS grp
    FROM SEAT_RESERVE
),
RESERVER AS (
    SELECT
        LINE,
        grp,
        MIN(SEAT_NO) AS SEAT_F,
        MAX(SEAT_NO) AS SEAT_T
    FROM RESERVER_CHECK
    GROUP BY grp
)
SELECT
    LINE,
    SEAT_F,
    SEAT_T
FROM RESERVER
ORDER BY LINE DESC, SEAT_F ASC;