with tmp as (
select
    i.PORT_CODE,
    p.PORT_NAME,
    sum(case when i.KIND_CODE = '110' then i.AMT END) AMT_IN,
    sum(case when i.KIND_CODE = '120' then i.AMT END) AMT_OUT
from IMMIGRATION i
left join PORT p
    on i.PORT_CODE = p.PORT_CODE
left join GRP g
    on i.GROUP_CODE = g.GROUP_CODE
where
    g.GROUP_NAME = '外国人'
group by 1
)
select
    PORT_CODE '港コード',
    PORT_NAME '港名',
    AMT_IN '入国者数',
    AMT_OUT '出国者数',
    AMT_IN - AMT_OUT '差分'
from tmp
where AMT_IN > AMT_OUT
order by 5 desc, 1 desc