with IN_T as
    (
select
PORT_CODE,
GROUP_CODE,
AMT
from IMMIGRATION
where KIND_CODE='110'
),
    OUT_T as
        (
            select
                PORT_CODE,
                GROUP_CODE,
                AMT
            from IMMIGRATION
            where KIND_CODE='120'
        )
select 
PORT.PORT_CODE as '港コード',
PORT.PORT_NAME as '港名',
IN_T.AMT as '入国者数',
OUT_T.AMT as '出国者数',
(IN_T.AMT - OUT_T.AMT) as '差分'

from IN_T inner join OUT_T on IN_T.PORT_CODE=OUT_T.PORT_CODE and
                              IN_T.GROUP_CODE=OUT_T.GROUP_CODE 
inner join PORT on IN_T.PORT_CODE=PORT.PORT_CODE

order by 5 desc,1 desc;