select
t1.PORT_CODE as 港コード,
p.PORT_NAME as 港名,
t1.AMT as 入国者数,
t2.AMT as 出国者数,
t1.AMT - t2.AMT as 差分
from IMMIGRATION as t1
inner join PORT as p
on t1.PORT_CODE = p.PORT_CODE
inner join IMMIGRATION as t2
on t1.PORT_CODE = t2.PORT_CODE
and t2.KIND_CODE = '120'

where t1.KIND_CODE = '110'
and t1.GROUP_CODE = '120'
and t1.AMT >= t2.AMT
order by
差分 desc,t1.PORT_CODE desc