WITH t AS(
SELECT LINE_ID AS LINE, SEAT_NO AS seat,
SUM(RSV_STATUS)OVER(PARTITION BY LINE_ID ORDER BY SEAT_NO RANGE 2 preceding) AS flag
FROM SEAT_RESERVE
)
SELECT
    LINE
    , SEAT - 2 AS SEAT_F
    , SEAT AS SEAT_T
FROM
    t
WHERE
    flag = 0
    AND SEAT >= 3
ORDER BY
    LINE DESC
    , SEAT_F