select
    PORT.PORT_CODE as "港コード",
    PORT.PORT_NAME as "港名",
    im_in.AMT as "入国者数",
    im_out.AMT as "出国者数",
    im_in.AMT - im_out.AMT as "差分"
from
    PORT
    join IMMIGRATION im_in on PORT.PORT_CODE = im_in.PORT_CODE
    and im_in.KIND_CODE = "110"
    and im_in.GROUP_CODE = "120"
    join IMMIGRATION im_out on PORT.PORT_CODE = im_out.PORT_CODE
    and im_out.KIND_CODE = "120"
    and im_out.GROUP_CODE = "120"
where
    "差分" > 0
group by
    PORT.PORT_CODE
order by
    "差分" desc,
    "港コード" desc;