SELECT
    t1.PORT_CODE '港コード',
    t1.PORT_NAME '港名',
    SUM(CASE WHEN t2.KIND_CODE = 110 THEN t2.AMT ELSE 0 END) '入国者数',
    SUM(CASE WHEN t2.KIND_CODE = 120 THEN t2.AMT ELSE 0 END) '出国者数',
    SUM(CASE WHEN t2.KIND_CODE = 110 THEN t2.AMT ELSE 0 END) - SUM(CASE WHEN t2.KIND_CODE = 120 THEN t2.AMT ELSE 0 END) '差分'
FROM
    IMMIGRATION t2
JOIN
    PORT t1
ON
    t1.PORT_CODE = t2.PORT_CODE
GROUP BY
    t1.PORT_CODE
HAVING
    SUM(CASE WHEN t2.KIND_CODE = 110 THEN t2.AMT ELSE 0 END) - SUM(CASE WHEN t2.KIND_CODE = 120 THEN t2.AMT ELSE 0 END) > 0
ORDER BY
    差分 DESC,
    港コード DESC
;