SELECT 
    i.ITEM_CODE as CODE,
    CASE
        WHEN i.ITEM_NAME != ih.ITEM_NAME OR ih.ITEM_NAME IS NULL THEN i.ITEM_NAME
        ELSE NULL
    END AS NAME
FROM ITEM AS i
LEFT JOIN 
    (
        SELECT
            ITEM_CODE,
            ITEM_NAME
        FROM ITEM_HISTORY
    ) AS ih
ON i.ITEM_CODE = ih.ITEM_CODE
ORDER BY i.ITEM_CODE DESC;