SELECT 
    LINE_ID,
    MIN(SEAT_NO) AS SEAT_F,
    MIN(SEAT_NO) + 1 AS SEAT_S,
    MIN(SEAT_NO) + 2 AS SEAT_T
FROM 
    SEAT_RESERVE
WHERE 
    RSV_STATUS = 0
GROUP BY 
    LINE_ID, 
    FLOOR((SEAT_NO - 1) / 3)
ORDER BY 
    LINE_ID DESC, 
    SEAT_F ASC;