WITH t1 AS(
    SELECT
        *,
        row_number() OVER (PARTITION BY PF_CODE ORDER BY AMT DESC, NATION_CODE) AS rn
    FROM FOREIGNER
)

, t2 AS(
    SELECT
        PF_CODE,
        SUM(CASE rn WHEN 1 THEN AMT ELSE 0 END) AS c1,
        MAX(CASE rn WHEN 1 THEN NATION_CODE ELSE "" END) AS c2
    FROM t1
    GROUP BY PF_CODE
)

SELECT * FROM t2