WITH RECURSIVE
  range(x) AS (
    SELECT 1
    UNION ALL
    SELECT x+1 FROM range WHERE x<13
  ),
  consecutive_seats AS (
    SELECT 
      s1.LINE_ID,
      s1.SEAT_NO AS SEAT_F,
      s3.SEAT_NO AS SEAT_T
    FROM 
      SEAT_RESERVE s1
      JOIN SEAT_RESERVE s2 ON s1.LINE_ID = s2.LINE_ID AND s2.SEAT_NO = s1.SEAT_NO + 1
      JOIN SEAT_RESERVE s3 ON s1.LINE_ID = s3.LINE_ID AND s3.SEAT_NO = s1.SEAT_NO + 2
    WHERE 
      s1.RSV_STATUS = 0 AND s2.RSV_STATUS = 0 AND s3.RSV_STATUS = 0
  )
SELECT 
  cs.LINE_ID AS LINE,
  MIN(cs.SEAT_F) AS SEAT_F,
  MIN(cs.SEAT_T) AS SEAT_T
FROM 
  consecutive_seats cs
GROUP BY 
  cs.LINE_ID
ORDER BY 
  cs.LINE_ID DESC, 
  MIN(cs.SEAT_F) ASC;