select
    p.port_code 港コード,
    p.port_name 港名,
    i1.amt 入国者数,
    i2.amt 出国者数,
    i1.amt - i2.amt 差分
from IMMIGRATION i1
join PORT p on i1.port_code = p.port_code
join IMMIGRATION i2
    on i1.port_code = i2.port_code
    and i1.group_code = i2.group_code
    and i2.kind_code = '120'
where 1 = 1
and i1.group_code = '120'
and i1.kind_code = '110'
and i1.amt > i2.amt
order by 5 desc, 1 desc
;