select 
b.PORT_CODE as 港コード,
a.PORT_NAME as 港名,
sum(case when b.KIND_CODE = '110' then b.AMT end) as 入国者数,
sum(case when b.KIND_CODE = '120' then b.AMT end) as 出国者数,
sum(case when b.KIND_CODE = '110' then b.AMT end) -
sum(case when b.KIND_CODE = '120' then b.AMT end) as 差分
from  IMMIGRATION b
inner join  PORT a on a.PORT_CODE = b.PORT_CODE
group by b.PORT_CODE
having (sum(case when b.KIND_CODE = '110' then b.AMT end) -
sum(case when b.KIND_CODE = '120' then b.AMT end)) > 0
order by (sum(case when b.KIND_CODE = '110' then b.AMT end) -
sum(case when b.KIND_CODE = '120' then b.AMT end)) DESC,
b.PORT_CODE DESC;