WITH SUB1 AS (
  SELECT DISTINCT
    T1.PORT_CODE,
    IFNULL((SELECT AMT FROM IMMIGRATION WHERE PORT_CODE = T1.PORT_CODE AND KIND_CODE = '110'), 0) AS AMT_IN,
    IFNULL((SELECT AMT FROM IMMIGRATION WHERE PORT_CODE = T1.PORT_CODE AND KIND_CODE = '120'), 0) AS AMT_OUT
  FROM
    IMMIGRATION AS T1
)
SELECT
  T1.PORT_CODE AS 港コード,
  T2.PORT_NAME AS 港名,
  T1.AMT_IN AS 入国者数,
  T1.AMT_OUT AS 出国者数,
  T1.AMT_IN - T1.AMT_OUT AS 差分
FROM
  SUB1 AS T1
INNER JOIN
  PORT AS T2
ON
  T1.PORT_CODE = T2.PORT_CODE
WHERE
  T1.AMT_IN > T1.AMT_OUT
ORDER BY
  差分 DESC,
  T1.PORT_CODE DESC
;