select
I.ITEM_CODE CODE,
case 
when I.ITEM_NAME != IH.ITEM_NAME then I.ITEM_NAME
when I.ITEM_NAME = IH.ITEM_NAME then 'NULL'
when IH.ITEM_NAME is null then I.ITEM_NAME
end as NAME
from ITEM I
left outer join ITEM_HISTORY IH on I.ITEM_CODE = IH.ITEM_CODE
order by CODE desc