with diff as (
    select
        i.item_code CODE,
        i.item_name NAME,
        'ADDED' COMP_RSLT
    from item i
    left join item_history ih
    on i.item_code = ih.item_code
    where ih.item_code is null
    union
    select
        ih.item_code CODE,
        ih.item_name NAME,
        'DELETED' COMP_RSLT
    from item_history ih
    left join item i
    on ih.item_code = i.item_code
    where i.item_code is null
    union
    select
        i.item_code CODE,
        i.item_name NAME,
        'UPDATED' COMP_RSLT
    from item i
    left join item_history ih
    on i.item_code = ih.item_code
    where i.user_update_datetime != ih.user_update_datetime
)
select * from diff
order by CODE desc