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 IM
INNER JOIN PORT P ON P.PORT_CODE = IM.PORT_CODE
INNER JOIN IMMIGRATION IM2 ON IM2.PORT_CODE = IM.PORT_CODE 
	AND IM2.GROUP_CODE = IM.GROUP_CODE 
	AND IM2.KIND_CODE = '120' 
WHERE IM.KIND_CODE = '110'
AND IM.GROUP_CODE = '120'
AND 差分 > 0
ORDER BY 差分 DESC, 港コード DESC