select
      a.PORT_CODE as "港コード"
    , PORT.PORT_NAME as "港名"
    , a.immigration as "入国者数"
    , a.departure as "出国者数"
    , a.diff as "差分"
from
    (
    select
          PORT_CODE
        , immigration
        , departure
        , immigration - departure as diff
    from
        (
        select
              PORT_CODE
            , max(case when KIND_CODE = 110 then AMT end) as immigration
            , max(case when KIND_CODE = 120 then AMT end) as departure
        from
            IMMIGRATION
        where
            GROUP_CODE = 120
        group by PORT_CODE
        )
    where
        immigration > departure
    ) a
    left outer join PORT using(PORT_CODE)
order by
    a.diff desc, a.PORT_CODE asc