select
    im.port_code as 港コード,
    p.port_name as 港名,
    im.amt as 入国者数,
    im2.amt as 出国者数,
    im.amt-im2.amt as 差分
from
    IMMIGRATION as im
    inner join PORT as p on p.PORT_CODE=im.PORT_CODE
    inner join GRP as g on g.GRouP_CODE=im.GRouP_CODE
    inner join IMMIGRATION as im2 on im.port_code=im2.port_code and im2.kind_code=120
where
    g.group_name="外国人" and im.KIND_CODE=110 and im.amt > im2.amt
order by
    差分 desc,港コード desc
;