select
    p.port_code as "港コード",
    port_name as "港名",
    i.total as "入国者数",
    o.total as "出国者数",
    i.total - o.total as "差分"
from port as p
inner join (
    select port_code, sum(amt) as total
    from immigration
    where group_code = 110 and kind_code = 110
    group by port_code
    ) as i on i.port_code = p.port_code
inner join (
    select im.port_code, sum(amt) as total
    from immigration as im
    where group_code = 110 and kind_code = 120
    group by port_code
    ) as o on o.port_code = p.port_code
where "差分" > 0
order by "差分" desc, p.port_code desc;