SELECT
    t.PORT_CODE AS [港コード]
    , p.PORT_NAME AS [港名]
    , t.im AS [入国者数]
    , t.em AS [出国者数]
    , t.im - t.em AS [差分]
FROM
    (
    SELECT
        PORT_CODE
        , SUM(IIF(KIND_CODE = '110', AMT, 0)) AS im
        , SUM(IIF(KIND_CODE = '120', AMT, 0)) AS em
    FROM
        IMMIGRATION
    WHERE
        GROUP_CODE = '120'
    GROUP BY
        PORT_CODE
    ) AS t
INNER JOIN
    PORT AS p
ON
    t.PORT_CODE = p.PORT_CODE
WHERE
    [差分] > 0
ORDER BY
    [差分] DESC
    , [港コード] DESC
;