with st as (
select item.item_code as ca, item.item_name as na, item_history.item_code as cb, item_history.item_name as nb, item.user_update_datetime as ua, item_history.user_update_datetime as ub from item full join item_history on item.item_code = item_history.item_code
)
, st2 as (select 
coalesce(ca, cb) as CODE
, coalesce(na, nb) as NAME
, case 
when ua is null then 'DELETED'
when ub is null then 'ADDED'
else 'UPDATED'
end as COMP_RSLT
from st where ua is not ub
)
select * from st2
order by CODE desc