select
    port_code as `港コード`,
    port_name as `港名`,
    amt_in as `入国者数`,
    amt_out as `出国者数`,
    amt_in - amt_out as `差分`
from
    (
        select
            ti.PORT_CODE as port_code,
            tp.PORT_NAME as port_name,
            TOTAL(IIF(KIND_CODE = 110, AMT, 0)) as amt_in,
            TOTAL(IIF(KIND_CODE = 120, AMT, 0)) as amt_out
        from
            IMMIGRATION as ti
            left join PORT as tp on ti.PORT_CODE = tp.PORT_CODE
            left join GRP as tg on ti.GROUP_CODE = tg.GROUP_CODE
        where
            tg.GROUP_NAME = "外国人"
        group by
            ti.PORT_CODE
    )
where
    amt_in > amt_out
order by
    `差分` desc;