select
    TBLA.ITEM_CODE as CODE,
    case
        when TBLA.ITEM_NAME = TBLB.ITEM_NAME then 'NULL'
        else TBLA.ITEM_NAME
    end as NAME
from
    ITEM as TBLA
left outer join ITEM_HISTORY TBLB on TBLA.ITEM_CODE = TBLB.ITEM_CODE
order by
    1 desc