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