SELECT 
 ITEM_CODE AS CODE
,ITEM_NAME AS NAME
,'ADDED' AS COMP_RSLT
FROM ITEM_HISTORY
WHERE ITEM_CODE NOT IN (SELECT ITEM_CODE FROM ITEM)
UNION
SELECT 
 ITEM_CODE AS CODE
,ITEM_NAME AS NAME
,'DELETED' AS COMP_RSLT
FROM ITEM
WHERE ITEM_CODE NOT IN (SELECT ITEM_CODE FROM ITEM_HISTORY)
UNION
SELECT 
 T1.ITEM_CODE AS CODE
,T1.ITEM_NAME AS NAME
,'UPDATED' AS COMP_RSLT
FROM ITEM AS T1
INNER JOIN ITEM_HISTORY AS T2 ON T1.ITEM_CODE = T2.ITEM_CODE
WHERE T1.USER_UPDATE_DATETIME != T2.USER_UPDATE_DATETIME;