select i.PORT_CODE as 港コード,
p.PORT_NAME as 港名,
i.amt as 入国者数,
i2.amt as 出国者数,
i.amt-i2.amt as 差分
from IMMIGRATION as i
inner join IMMIGRATION as i2 on i.PORT_CODE=i2.PORT_CODE and i2.KIND_CODE=120 and i2.GROUP_CODE=120
inner join GRP as g on i.GROUP_CODE=g.GROUP_CODE
inner join PORT as p on i.PORT_CODE=p.PORT_CODE
where i.KIND_CODE=110 and i.GROUP_CODE=120 and i.amt-i2.amt>0
order by 5 desc, 1 desc