select
A.PORT_CODE as '港コード',
B.PORT_NAME as '港名',
SUM(CASE WHEN A.KIND_CODE=110 then A.AMT else 0 end) as '入国者数',
SUM(CASE WHEN A.KIND_CODE=120 then A.AMT else 0 end) as '出国者数',
SUM(CASE WHEN A.KIND_CODE=110 then A.AMT else 0 end) - SUM(CASE WHEN A.KIND_CODE=120 then A.AMT else 0 end) as '差分'
from 
IMMIGRATION A,PORT B
where
A.PORT_CODE = B.PORT_CODE
group by
A.PORT_CODE 
order by 
SUM(CASE WHEN A.KIND_CODE=110 then A.AMT else 0 end) -SUM(CASE WHEN A.KIND_CODE=120 then A.AMT else 0 end)  DESC,
A.PORT_CODE DESC
;