SELECT
PORT.PORT_CODE AS "港コード",
PORT.PORT_NAME AS "港名",
INER.AMT AS "入国者数",
OUER.AMT AS "出国者数",
INER.AMT - OUER.AMT AS "差分"
FROM
    IMMIGRATION AS INER
    INNER JOIN GRP
        ON INER.GROUP_CODE = GRP.GROUP_CODE
        AND GRP.GROUP_CODE = 120
    INNER JOIN PORT
        ON INER.PORT_CODE = PORT.PORT_CODE
        AND INER.KIND_CODE = 110
    INNER JOIN IMMIGRATION AS OUER
        ON OUER.GROUP_CODE = INER.GROUP_CODE
        AND INER.KIND_CODE = 120
ORDER BY
    差分 DESC,
    港コード DESC;