WITH TMP(LINE, TWO_PRE, CUR) AS (
    SELECT
        LINE_ID,
        MIN(SEAT_NO) OVER(ROWS BETWEEN 2 PRECEDING AND 2 PRECEDING),
        SEAT_NO
    FROM 
    (SELECT 
        LINE_ID,
        SEAT_NO
    FROM SEAT_RESERVE
    WHERE RSV_STATUS='0'
    ORDER BY LINE_ID DESC, SEAT_NO ASC)
)
SELECT 
    LINE,
    TWO_PRE AS SEAT_F,
    CUR AS SEAT_T
FROM TMP
WHERE CUR-TWO_PRE=2;