SELECT IMMI_NYU.PORT_CODE AS 港コード,
        PORT_NAME AS 港名,
        IMMI_NYU.AMT AS 入国者数,
        IMMI_SYU.AMT AS 出庫者数,
        (IMMI_NYU.AMT - IMMI_SYU.AMT) AS 差分
    FROM (SELECT PORT_CODE, AMT FROM IMMIGRATION WHERE GROUP_CODE = 120 AND KIND_CODE = 110) AS IMMI_NYU,
          (SELECT PORT_CODE, AMT FROM IMMIGRATION WHERE GROUP_CODE = 120 AND KIND_CODE = 120) AS IMMI_SYU,
          PORT
WHERE
    IMMI_NYU.PORT_CODE = IMMI_SYU.PORT_CODE
    AND PORT.PORT_CODE = IMMI_NYU.PORT_CODE
    AND IMMI_NYU.AMT - IMMI_SYU.AMT > 0
ORDER BY 5 DESC