SELECT
    ITEM_CODE AS CODE
    , ITEM.ITEM_NAME AS NAME
    , CASE
        WHEN ITEM_HISTORY.ITEM_CODE IS NULL THEN 'ADDED'
        WHEN ITEM.ITEM_CODE IS NULL THEN 'DELETED'
        WHEN ITEM.USER_UPDATE_DATETIME > ITEM_HISTORY.USER_UPDATE_DATETIME THEN 'UPDATED'
    END AS COMP_RSLT
FROM ITEM
FULL OUTER JOIN ITEM_HISTORY USING (ITEM_CODE)
WHERE COMP_RSLT IS NOT NULL
ORDER BY CODE DESC
;