with
immigration_in as(
select
    PORT_CODE, AMT
from
    IMMIGRATION
where
    GROUP_CODE = 120 and KIND_CODE = 110
)

, immigration_out as (
select
    PORT_CODE, AMT
from
    IMMIGRATION
where
    GROUP_CODE = 120 and KIND_CODE = 120
)

select
      p.PORT_CODE as 港コード
    , p.PORT_NAME as 港名
    , ii.AMT as 入国者数
    , io.AMT as 出国者数
    , ii.AMT - io.AMT as 差分
from
    PORT as p
    join
        immigration_in as ii
    on
        p.PORT_CODE = ii.PORT_CODE
    join
        immigration_out as io
    on
        p.PORT_CODE = io.PORT_CODE
where
    差分 > 0