select itm.ITEM_CODE as CODE
,case
  when itm_his.ITEM_NAME is null then itm.ITEM_NAME
  when itm.ITEM_NAME <> itm_his.ITEM_NAME then itm.ITEM_NAME
  else null
 end as NAME
from ITEM itm
left join ITEM_HISTORY itm_his
on  itm_his.ITEM_CODE = itm.ITEM_CODE
order by itm.ITEM_CODE desc