SELECT 
CASE WHEN IT.ITEM_CODE IS NULL THEN IH.ITEM_CODE ELSE IT.ITEM_CODE END AS CODE
,CASE WHEN IT.ITEM_NAME IS NULL THEN IH.ITEM_NAME ELSE IT.ITEM_NAME END AS NAME
,CASE WHEN IT.ITEM_CODE IS NULL THEN 'DELETED' 
    WHEN IH.ITEM_CODE IS NULL THEN 'ADDED' 
    WHEN IT.USER_UPDATE_DATETIME<>IH.USER_UPDATE_DATETIME THEN 'UPDATED' END
    AS COMP_RSLT


FROM ITEM AS IT
    FULL JOIN ITEM_HISTORY AS IH
    ON IT.ITEM_CODE = IH.ITEM_CODE

WHERE COMP_RSLT IS NOT NULL
ORDER BY CODE DESC