SELECT
 IM.PORT_CODE AS "港コード",
 P.PORT_NAME AS "港名",
 SUM(CASE WHEN IM.KIND_CODE=110 THEN AMT END) AS "入国者数",
 SUM(CASE WHEN IM.KIND_CODE=120 THEN AMT END) AS "出国者数",
 SUM(CASE WHEN IM.KIND_CODE=110 THEN AMT END)-SUM(CASE WHEN IM.KIND_CODE=120 THEN AMT END) AS "差分"
FROM IMMIGRATION IM
INNER JOIN PORT P ON IM.PORT_CODE = P.PORT_CODE
INNER JOIN GRP G ON IM.GROUP_CODE = G.GROUP_CODE
 WHERE G.GROUP_NAME = "外国人"
GROUP BY 1
ORDER BY 5 DESC,1 DESC