SELECT PO.PORT_CODE AS 港コード
,PORT_NAME AS 港名
,IMIN.AMT AS 入国者数
,IM.AMT AS 出国者数
,IMIN.AMT- IM.AMT AS 差分
FROM IMMIGRATION IM
LEFT JOIN PORT PO
ON IM.PORT_CODE=PO.PORT_CODE
LEFT JOIN GRP GRP
ON IM.GROUP_CODE  = GRP.GROUP_CODE 
INNER JOIN IMMIGRATION IMIN
ON IMIN.PORT_CODE  = IM.PORT_CODE 
AND IMIN.GROUP_CODE =IM.GROUP_CODE 
AND IMIN.GROUP_CODE='120'
AND IMIN.KIND_CODE='110'
WHERE 1=1
AND 差分>0
AND IM.GROUP_CODE='120'
AND IM.KIND_CODE='120'

ORDER BY 差分 desc,
港コード desc