SELECT
	port.port_code AS "港コード",
	port.port_name AS "港名",
	sum(
		CASE immigration.kind_code
		WHEN 110 THEN
			immigration.amt
		ELSE
			0
		END) AS "入国者数",
	sum(
		CASE immigration.kind_code
		WHEN 120 THEN
			immigration.amt
		ELSE
			0
		END) AS "出国者数",
	sum(
		CASE immigration.kind_code
		WHEN 110 THEN
			immigration.amt
		ELSE
			- immigration.amt
		END) AS "差分"
FROM
	immigration,
	port USING (port_code), grp USING (group_code)
WHERE
	grp.group_code = 120
GROUP BY
	port.port_code
HAVING
	"差分" > 0
ORDER BY
	"差分" DESC,
	"港コード" DESC