SELECT
    I.ITEM_CODE CODE,
    CASE 
        WHEN I.ITEM_NAME == IH.ITEM_NAME THEN NULL
        WHEN IH.ITEM_NAME IS NULL THEN I.ITEM_NAME
        ELSE I.ITEM_NAME
    END NAME
FROM
    ITEM I LEFT JOIN 
    ITEM_HISTORY IH ON I.ITEM_CODE = IH.ITEM_CODE
ORDER BY I.ITEM_CODE DESC