select
t1.ITEM_CODE as CODE,
case
    when
        t1.ITEM_NAME != t2.ITEM_NAME then t1.ITEM_NAME
    when
        t1.ITEM_NAME = t2.ITEM_NAME then NULL
    when
        t2.ITEM_NAME is null then t1.ITEM_NAME
    end as NAME
from ITEM as t1
left join ITEM_HISTORY as t2
on t1.item_code = t2.item_code
order by code desc