SELECT
    p.PORT_CODE AS 港コード
    , p.PORT_NAME AS 港名
    , i0.AMT AS 入国者数
    , i1.AMT AS 出国者数
    , (i0.AMT - i1.AMT) AS 差分 
FROM
    IMMIGRATION AS i0 
   INNER JOIN IMMIGRATION AS i1 
        ON i1.PORT_CODE = i0.PORT_CODE 
        AND i1.GROUP_CODE = i0.GROUP_CODE 
        AND i1.KIND_CODE = '120' 
   INNER JOIN PORT AS p 
        ON p.PORT_CODE = i0.PORT_CODE 
WHERE
    i0.GROUP_CODE = '120' 
    AND i0.KIND_CODE = '110' 
    AND i0.AMT > i1.AMT 
ORDER BY
    差分 DESC
    , i0.PORT_CODE DESC;