SELECT
    n.item_code as CODE
    ,case
        when n.item_name = h.item_name then NULL
        when n.item_name <> h.item_name then n.item_name
        when h.item_name is null then n.item_name
     end as NAME
FROM
    item as n
LEFT JOIN
    item_history as h
ON
    n.item_code =h.item_code
ORDER BY
    n.item_code DESC;