with tb as (
select
    im.PORT_CODE,
    im.AMT,
    im.KIND_CODE
from IMMIGRATION im
join GRP g on g.GROUP_CODE == im.GROUP_CODE
where g.GROUP_CODE == '120'
group by im.PORT_CODE, im.KIND_CODE
),
tb1 as (
select tb.PORT_CODE, AMT as AMT1 from tb
where tb.KIND_CODE == '110'
group by tb.PORT_CODE
),
tb2 as (
select tb.PORT_CODE, AMT as AMT2 from tb
where tb.KIND_CODE == '120'
group by tb.PORT_CODE
)

select
  p.PORT_CODE as '港コード',
  p.PORT_NAME as '港名',
  tb1.AMT1 as '入国者数',
  tb2.AMT2 as '出国者数',
  abs(tb1.AMT1 - tb2.AMT2) as '差分'
from PORT p
join tb1 on tb1.PORT_CODE == p.PORT_CODE
join tb2 on tb2.PORT_CODE == p.PORT_CODE
order by 差分 desc, p.PORT_CODE desc