select 
    p.PORT_CODE as '港コード',
    p.PORT_NAME as '港名',
    i1.AMT110 as '入国者数',
    i1.AMT120 as '出国者数'--,
    --sum(case when i.KIND_CODE = '110' then i.AMT else 0 end ) - sum(case when i.KIND_CODE = '120' then i.AMT else 0 end ) as '差分'

from 
    PORT as p
    inner join 
    (select
        PORT_CODE,
        sum(case when KIND_CODE = '110' then AMT else 0 end ) as AMT110,
        sum(case when KIND_CODE = '120' then AMT else 0 end ) as AMT120
    from
        IMMIGRATION as i
        inner join 
        GRP as g
        on i.GROUP_CODE =g.GROUP_CODE 
    where 
        KIND_CODE in ('110','120')
    group by
        PORT_CODE
    having AMT110 - AMT120 > 0
        )
        as i1
    on p.PORT_CODE = i1.PORT_CODE
order by 
    --DESC,
    i1.PORT_CODE DESC