SELECT
    B.PORT_CODE "港コード",
    B.PORT_NAME "港名",
    INAMT "入国者数",
    OUTAMT "出国者数",
    INAMT - OUTAMT "差分"
FROM
    (SELECT
        PORT_CODE,
        SUM(CASE WHEN KIND_CODE = 110 THEN AMT ELSE 0 END) AS INAMT,
        SUM(CASE WHEN KIND_CODE = 120 THEN AMT ELSE 0 END) AS OUTAMT
    FROM
        IMMIGRATION
    WHERE
        GROUP_CODE = 120
    GROUP BY
        PORT_CODE
    ) AS A
JOIN
    PORT AS B
ON A.PORT_CODE = B.PORT_CODE
ORDER BY
    "差分" DESC,
    B.PORT_CODE DESC