SELECT
I.PORT_CODE AS '港コード',
P.PORT_NAME AS '港名',
I.AMT AS '入国者数',
OI.AMT AS '出国者数',
I.AMT-OI.AMT AS '差分'
FROM IMMIGRATION I
INNER JOIN PORT P
ON I.PORT_CODE = P.PORT_CODE
INNER JOIN
(SELECT PORT_CODE,AMT FROM IMMIGRATION WHERE GROUP_CODE = 120 AND KIND_CODE = '120')OI
ON I.PORT_CODE = OI.PORT_CODE
WHERE GROUP_CODE = 120
AND KIND_CODE = '110'
AND 差分> 0
ORDER BY 差分 DESC,I.PORT_CODE DESC