--一位の人のコードめちゃ綺麗
SELECT
    FIRST.LINE_ID AS LINE,
    FIRST.SEAT_NO AS SEAT_F,
    THIRD.SEAT_NO AS SEAT_T
FROM
    SEAT_RESERVE AS
    FIRST
INNER JOIN
    SEAT_RESERVE AS
    SECOND ON
    SECOND.LINE_ID = FIRST.LINE_ID AND
    SECOND.SEAT_NO = FIRST.SEAT_NO + 1
INNER JOIN
    SEAT_RESERVE AS
    THIRD ON
    THIRD.LINE_ID = FIRST.LINE_ID AND
    THIRD.SEAT_NO = FIRST.SEAT_NO + 2
WHERE 
    FIRST.RSV_STATUS = 0 AND
    SECOND.RSV_STATUS = 0 AND
    THIRD.RSV_STATUS = 0
ORDER BY
    FIRST.LINE_ID DESC,
    FIRST.SEAT_NO ASC