WITH ITEM_MERGED AS (
    SELECT
        ITEM.*,
        CASE
        WHEN ITEM_HISTORY.ITEM_CODE IS NULL
            THEN 'ADDED'
        WHEN ITEM_HISTORY.USER_UPDATE_DATETIME <> ITEM.USER_UPDATE_DATETIME
            THEN 'UPDATED'
        ELSE
            NULL
        END AS COMP_RSLT
    FROM
        ITEM
    LEFT JOIN
        ITEM_HISTORY ON
        ITEM_HISTORY.ITEM_CODE = ITEM.ITEM_CODE
    UNION ALL
    SELECT
        ITEM_HISTORY.*,
        'DELETED' AS COMP_RSLT
    FROM
        ITEM_HISTORY
    LEFT JOIN
        ITEM ON
        ITEM.ITEM_CODE = ITEM_HISTORY.ITEM_CODE
    WHERE
        ITEM.ITEM_CODE IS NULL
)
SELECT
    ITEM_CODE AS CODE,
    ITEM_NAME AS NAME,
    COMP_RSLT
FROM
    ITEM_MERGED
WHERE
    COMP_RSLT IS NOT NULL
ORDER BY
    CODE DESC