SELECT 
    I.PORT_CODE AS '港コード',
    P.PORT_NAME AS '港名',
    SUM(CASE WHEN I.KIND_CODE = '110' THEN I.AMT END) AS '入国者数',
    SUM(CASE WHEN I.KIND_CODE = '120' THEN I.AMT END) AS '出国者数',
    SUM(CASE WHEN I.KIND_CODE = '110' THEN I.AMT ELSE -I.AMT END) AS '差分'
FROM
    IMMIGRATION AS I
INNER JOIN
    GRP AS G ON I.GROUP_CODE = G.GROUP_CODE
INNER JOIN 
    PORT AS P ON I.PORT_CODE = P.PORT_CODE
WHERE
    G.GROUP_NAME = '外国人'
    AND I.KIND_CODE IN ('110', '120')
GROUP BY
    I.PORT_CODE
HAVING 差分 > 0
ORDER BY
    差分 DESC, 港コード DESC