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