SELECT
    A.LINE_ID AS LINE 
    ,A.SEAT_NO AS SEAT_F
    ,C.SEAT_NO AS SEAT_T
FROM 
    SEAT_RESERVE AS A
     LEFT JOIN  SEAT_RESERVE AS B
        ON A.SEAT_NO +1 = B.SEAT_NO
        --ND A.LINE =B.LINE
     LEFT JOIN SEAT_RESERVE AS C
        ON A.SEAT_NO +2 = C.SEAT_NO
        --AND A.LINE =c.LINE
WHERE
    A.RSV_STATUS='0'
    AND B.RSV_STATUS='0'
    AND C.RSV_STATUS='0'
GROUP BY 
    LINE,
    SEAT_F,
    SEAT_T
ORDER BY 
    LINE DESC,
    SEAT_F ASC