SELECT * FROM (
    SELECT 
        ITEM_CODE AS CODE, 
        ITEM_NAME AS NAME, 
        'ADDED' AS COMP_RSLT
    FROM 
        ITEM
    WHERE 
        ITEM_CODE NOT IN (SELECT ITEM_CODE FROM ITEM_HISTORY)

    UNION ALL

    SELECT 
        I.ITEM_CODE AS CODE, 
        I.ITEM_NAME AS NAME, 
        'UPDATED' AS COMP_RSLT
    FROM 
        ITEM I
    JOIN 
        ITEM_HISTORY IH ON I.ITEM_CODE = IH.ITEM_CODE
    WHERE 
        I.USER_UPDATE_DATETIME > IH.USER_UPDATE_DATETIME

    UNION ALL

    SELECT 
        IH.ITEM_CODE AS CODE, 
        IH.ITEM_NAME AS NAME, 
        'DELETED' AS COMP_RSLT
    FROM 
        ITEM_HISTORY IH
    WHERE 
        IH.ITEM_CODE NOT IN (SELECT ITEM_CODE FROM ITEM)
) AS combined_results
ORDER BY CODE DESC;