SELECT PORT.PORT_CODE AS '港コード'
	, PORT.PORT_NAME AS '港名'
	, SUM(IMMIGRATION_IN.AMT) AS '入国者数'
	, SUM(IMMIGRATION_OUT.AMT) AS '出国者数'
	, SUM(IMMIGRATION_IN.AMT) - SUM(IMMIGRATION_OUT.AMT) AS '差分'
FROM PORT
INNER JOIN IMMIGRATION AS IMMIGRATION_IN
	ON PORT.PORT_CODE = IMMIGRATION_IN.PORT_CODE
		AND IMMIGRATION_IN.GROUP_CODE IN ('120')
		AND IMMIGRATION_IN.KIND_CODE = '110'
INNER JOIN IMMIGRATION AS IMMIGRATION_OUT
	ON PORT.PORT_CODE = IMMIGRATION_OUT.PORT_CODE
		AND IMMIGRATION_OUT.GROUP_CODE IN ('120')
		AND IMMIGRATION_OUT.KIND_CODE = '120'
GROUP BY PORT.PORT_CODE
	, PORT.PORT_NAME
ORDER BY (SUM(IMMIGRATION_IN.AMT) - SUM(IMMIGRATION_OUT.AMT)) DESC
	, PORT.PORT_CODE DESC