with st as (select
LINE_ID as LINE
, SEAT_NO as SN
from SEAT_RESERVE
where rsv_status = 0
)
, sv as (select * from st as st1
where exists (
select 1 from st as st2 where st1.LINE = st2.LINE and st1.SN + 1 = st2.SN
) and 
exists (
select 1 from st as st3 where st1.LINE = st3.LINE and st1.SN + 2 = st3.SN
))
select
LINE
, SN as SEAT_F
, SN + 2 as SEAT_T
from sv
order by LINE desc, SEAT_F