SELECT
    IT.ITEM_CODE AS CODE
    ,CASE
        WHEN IT.ITEM_NAME = IT_HIS.ITEM_NAME THEN 'NULL'
        ELSE IT.ITEM_NAME
    END AS NAME
FROM
    ITEM AS IT
LEFT JOIN
    ITEM_HISTORY AS IT_HIS
ON
    IT.ITEM_CODE = IT_HIS.ITEM_CODE
ORDER BY 
    IT.ITEM_CODE DESC