with tmp as (
select
    item_code
    ,item_name
from
    item i
where
    not exists (
        select
            1
        from
            item_history ih
        where
            i.item_code = ih.item_code
    )
),
tmp2 as (
select
    item_code
    ,item_name
from
    item_history ih
where
    not exists (
        select
            1
        from
            item i
        where
            i.item_code = ih.item_code
    )
),
tmp3 as (
select
    i.item_code
    ,i.item_name
from
    item i inner join item_history ih
    on i.item_code = ih.item_code
where
    i.user_update_datetime <> ih.user_update_datetime
),
tmp4 as (
select
    *
    ,'ADDED' as "COMP_RSLT"
from
    tmp
union all
select
    *
    ,'DELETED' as "COMP_RSLT"
from
    tmp2
union all
select
    *
    ,'UPDATED' as "COMP_RSLT"
from
    tmp3
)
select
    item_code "CODE"
    ,item_name "NAME"
    ,comp_rslt
from
    tmp4
order by
    item_code desc
;