SELECT
    it.item_code as CODE
    , it.item_name as NAME
    , CASE
        when ith.user_update_datetime IS NULL
            then 'ADDED'
        when it.user_update_datetime IS NULL
            then 'DELETED'
        when ith.user_update_datetime <> it.user_update_datetime
            then 'UPDATED'
        END as COMP_RSLT
FROM
    item as it
    FULL OUTER JOIN item_history as ith
    ON it.item_code = ith.item_code
WHERE
    it.user_update_datetime IS NOT ith.user_update_datetime
ORDER BY
    code desc;