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