--【問題9】
SELECT
	A.ITEM_CODE AS CODE
,	CASE
		WHEN A.ITEM_NAME = B.ITEM_NAME THEN 'NULL'
		ELSE A.ITEM_NAME
	END AS NAME
FROM
	ITEM A
LEFT OUTER JOIN
	ITEM_HISTORY B
ON
	A.ITEM_CODE = B.ITEM_CODE
ORDER BY
	A.ITEM_CODE  DESC