SELECT
    PT.PORT_CODE AS 港コード
    , PT.PORT_NAME AS 港名
    , IMM_110.AMT AS 入国者数
    , IMM_120.AMT AS 出国者数
    , IMM_110.AMT - IMM_120.AMT AS 差分
FROM
    IMMIGRATION AS IMM_110
    INNER JOIN PORT AS PT
        ON PT.PORT_CODE = IMM_110.PORT_CODE
    INNER JOIN IMMIGRATION AS IMM_120
        ON IMM_120.KIND_CODE = 120
        AND IMM_120.PORT_CODE = IMM_110.PORT_CODE
WHERE
    IMM_110.KIND_CODE = 110
    AND 差分 > 0
ORDER BY
    差分 DESC
    , IMM_110.PORT_CODE ASC;