with SUB as(
    select
        LINE_ID
        ,lag(SEAT_NO) over(partition by LINE_ID order by LINE_ID, SEAT_NO) as LAG1
        ,SEAT_NO
        ,lead(SEAT_NO) over(partition by LINE_ID order by LINE_ID, SEAT_NO) as LEAD1
    from SEAT_RESERVE
    where RSV_STATUS=0
    )
select
    LINE_ID as LINE
    ,LAG1 as SEAT_F
    ,LEAD1 as SEAT_T
from SUB
where LAG1+1=SEAT_NO and SEAT_NO+1=LEAD1
order by LINE_ID desc, LAG1 asc
;