WITH tmp AS (
    SELECT
        PORT_CODE,
        SUM(CASE WHEN KIND_CODE = "110" THEN AMT ELSE 0 END) AS nn,
        SUM(CASE WHEN KIND_CODE = "120" THEN AMT ELSE 0 END) AS ss,
        SUM(CASE WHEN KIND_CODE = "110" THEN AMT ELSE 0 END) - SUM(CASE WHEN KIND_CODE = "120" THEN AMT ELSE 0 END) AS dd
    FROM
        IMMIGRATION
    GROUP BY
        PORT_CODE
)


SELECT
i.PORT_CODE AS "港コード",
p.PORT_NAME AS "港名",
i.nn AS "入国者数",
i.ss AS "出国者数",
i.dd AS "差分"

FROM
tmp i
LEFT JOIN
PORT p
ON
p.PORT_CODE = i.PORT_CODE

WHERE
"差分" > 0
ORDER BY
"差分" DESC,
"港コード" DESC