WITH SUM_RSV_STATUS AS (
    SELECT
        LINE_ID
        , SEAT_NO
        , RSV_STATUS
        , SUM(RSV_STATUS) OVER(
                ORDER BY
                    LINE_ID
                ROWS 2 PRECEDING
            ) AS SUM_RSV_STATUS
    FROM
        SEAT_RESERVE
)
, SEAT_3_0 AS (
    SELECT
        LINE_ID AS LINE
        , SEAT_NO - 2 AS SEAT_F
        , SEAT_NO AS SEAT_T
    FROM
        SUM_RSV_STATUS
    WHERE
        SUM_RSV_STATUS = 0
    ORDER BY
        LINE DESC
        , SEAT_F ASC
)
SELECT
    *
FROM
    SEAT_3_0
WHERE
    SEAT_F > 0
;