select coalesce(i.item_code,ih.item_code) CODE
, coalesce(i.item_name,ih.item_name) NAME
, case when i.item_code is null then 'DELETED' 
when ih.item_code is null then 'ADDED'
else 'UPDATED'
end COMP_RSLT
from item i
full outer join item_history ih on
i.item_code = ih.item_code
where i.item_code is null 
or ih.item_code is null
or i.USER_UPDATE_DATETIME <> ih.USER_UPDATE_DATETIME
order by 1 desc