WITH
nyukoku AS(
    SELECT
    IMMIGRATION.PORT_CODE 
    , PORT.PORT_NAME 
    , AMT AS nyukoku_amt
    FROM
        IMMIGRATION
        INNER JOIN
        PORT
        ON
        IMMIGRATION.PORT_CODE = PORT.PORT_CODE
    WHERE
        IMMIGRATION.KIND_CODE = '110'
        AND
        IMMIGRATION.GROUP_CODE = '120'
)
, syukoku AS (
    SELECT
        IMMIGRATION.PORT_CODE 
        , PORT.PORT_NAME 
        , AMT AS syukoku_amt
    FROM
        IMMIGRATION
        INNER JOIN
        PORT
        ON
        IMMIGRATION.PORT_CODE = PORT.PORT_CODE
    WHERE
        IMMIGRATION.KIND_CODE = '120'
        AND
        IMMIGRATION.GROUP_CODE = '120'
)

SELECT
    nyukoku.PORT_CODE AS 港コード
    , nyukoku.PORT_NAME AS 港名
    , nyukoku_amt AS 入国者数
    , syukoku_amt AS 出国者数
    , nyukoku_amt - syukoku_amt AS 差分
FROM
    nyukoku
    INNER JOIN
    syukoku
    ON
    nyukoku.PORT_CODE = syukoku.PORT_CODE
WHERE
    nyukoku_amt - syukoku_amt > 0
ORDER BY
    差分 DESC
    , 港コード DESC
;