with merge_data as  (
    select
        IMMIGRATION.PORT_CODE,
        PORT.PORT_NAME,
        AMT,
        KIND_CODE
    from
        IMMIGRATION
    left join
        GRP
    on
        IMMIGRATION.GROUP_CODE = GRP.GROUP_CODE
    left join
        PORT
    on
        IMMIGRATION.PORT_CODE = PORT.PORT_CODE
),

entry_data as (
    select
        PORT_CODE,
        PORT_NAME,
        AMT as ENTRY_AMT
    from
        merge_data
    where
        KIND_CODE = '110'
),
departure_data as (
    select
        PORT_CODE,
        PORT_NAME,
        AMT as DEPARTURE_AMT
    from
        merge_data
    where
        KIND_CODE = '120'
),

amt_data as (
    select *
    from entry_data
    left join departure_data
    on entry_data.PORT_CODE = departure_data.PORT_CODE
)

select
    PORT_CODE as 港コード,
    PORT_NAME as 港名,
    ENTRY_AMT as 入国者数,
    DEPARTURE_AMT as 出国者数,
    ENTRY_AMT - DEPARTURE_AMT as 差分
from
    amt_data
where
    差分 > 0
order by
    差分 DESC,
    港コード DESC