SELECT
 IMI1.PORT_CODE AS "港コード",
 PORT.PORT_NAME AS "港名",
 IMI2.AMT AS "入国者数",
 IMI1.AMT AS "出国者数",
 IMI2.AMT - IMI1.AMT AS "差分"
FROM
 IMMIGRATION IMI1
INNER JOIN
 IMMIGRATION IMI2 ON IMI1.PORT_CODE = IMI2.PORT_CODE
 AND IMI2.GROUP_CODE = 120
 AND IMI2.KIND_CODE = 110
INNER JOIN GRP ON GRP.GROUP_CODE = IMI1.GROUP_CODE
INNER JOIN PORT ON PORT.PORT_CODE = IMI1.PORT_CODE
WHERE IMI1.GROUP_CODE = 120
 AND IMI1.KIND_CODE = 120
 AND IMI1.AMT < IMI2.AMT
GROUP BY IMI1.PORT_CODE
ORDER BY "差分" DESC, IMI1.PORT_CODE DESC;