WITH ROWNUM AS(
    SELECT *,row_number() over (partition by LINE_ID order by LINE_ID,SEAT_NO ASC) RENBAN
    FROM SEAT_RESERVE
),
NO_RSV AS(
    SELECT *
    FROM ROWNUM
    WHERE RSV_STATUS = '0'
),
RSV_DIFF AS(
    SELECT *,
            coalesce(CASE
                        WHEN RENBAN = 1 THEN NULL
                        WHEN RENBAN - 1 = LAG(RENBAN) over (order by LINE_ID,SEAT_NO) THEN 1
                        WHEN RENBAN - 1 <> LAG(RENBAN) over (order by LINE_ID,SEAT_NO) THEN RENBAN - 1
                     END
                    ,1) DIFF
    FROM NO_RSV
),
RSV_GROUP AS(
    SELECT *,
           RENBAN - SUM(DIFF) over (partition by LINE_ID order by LINE_ID,SEAT_NO ASC) groupdiff
    FROm RSV_DIFF
)

SELECT LINE_ID LINE,
       CASE
        WHEN MAX(RENBAN) - MIN(RENBAN) = 2 THEN MIN(RENBAN)
        WHEN MAX(RENBAN) - MIN(RENBAN) <> 2 THEN MIN(RENBAN)+1
       END SEAT_F,
       CASE
        WHEN MAX(RENBAN) - MIN(RENBAN) = 2 THEN MAX(RENBAN)
        WHEN MAX(RENBAN) - MIN(RENBAN) <> 2 THEN MAX(RENBAN)
       END SEAT_T
FROM RSV_GROUP
GROUP BY LINE_ID,groupdiff HAVING COUNT(*) >= 3