select x.item_code as'CODE',
x.item_name as 'NAME',
'UPDATED' as 'COMP_RSLT'
from item as x
inner join item_history as y
on x.item_code = y.item_code
and x.USER_UPDATE_DATETIME > y.USER_UPDATE_DATETIME
union all
select item_code as'CODE',item_name as 'NAME',
'ADDED' as 'COMP_RSLT'
from item
where item_code not in (select item_code from item_history)
union all
select item_code as'CODE',item_name as 'NAME',
'DELETED' as 'COMP_RSLT'
from item_history
where item_code not in (select item_code from item)
order by 1 desc