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