SELECT
    a.PORT_CODE AS 港コード
    , b.PORT_NAME AS 港名
    , SUM(CASE WHEN KIND_CODE = '110' THEN AMT ELSE 0 END) AS 入国者数
    , SUM(CASE WHEN KIND_CODE = '120' THEN AMT ELSE 0 END) AS 出国者数
    , SUM(
        CASE
            WHEN KIND_CODE = '110' THEN AMT
            WHEN KIND_CODE = '120' THEN -1 * AMT
            ELSE 0 
        END
    ) AS 差分
    
    
FROM
    IMMIGRATION AS a
    INNER JOIN PORT AS b
        ON a.PORT_CODE = b.PORT_CODE AND a.KIND_CODE IN ('110', '120')
    INNER JOIN GRP AS c
        ON a.GROUP_CODE = c.GROUP_CODE AND c.GROUP_CODE = '120'

GROUP BY 1,2

HAVING
    入国者数-出国者数 > 0

ORDER BY
    5 DESC, 1 DESC