select
  line_id as LINE,
  -- seat_no,
  lag(seat_no) over (partition by line_id order by line_id, seat_no) as SEAT_F,
  lead(seat_no) over (partition by seat_no order by line_id, seat_no) as SEAT_T
from
  SEAT_RESERVE
where
  RSV_STATUS = '0'
  and line_id = 'E'
  and (seat_no = seat_no + 1 and 
order by
  LINE_ID desc,
    SEAT_F;