SELECT
I.ITEM_CODE CODE,
CASE    WHEN IH.ITEM_NAME IS NULL THEN I.ITEM_NAME
        WHEN I.ITEM_NAME = IH.ITEM_NAME THEN NULL
        ELSE I.ITEM_NAME
        END
AS NAME
FROM ITEM I FULL OUTER JOIN ITEM_HISTORY IH
ON I.ITEM_CODE = IH.ITEM_CODE
WHERE I.ITEM_CODE IS NOT NULL
ORDER BY I.ITEM_CODE DESC