WITH T1 AS
(
SELECT ITEM_CODE
      ,ITEM_NAME
  FROM ITEM WK3
EXCEPT
SELECT ITEM_CODE
      ,ITEM_NAME
  FROM ITEM_HISTORY
),
T2 AS
(
SELECT ITEM_CODE
      ,ITEM_NAME
  FROM ITEM_HISTORY WK2
EXCEPT
SELECT ITEM_CODE
      ,ITEM_NAME
  FROM ITEM
),
T3 AS
(
SELECT WK1.ITEM_CODE
      ,WK1.ITEM_NAME
  FROM ITEM WK1
  LEFT JOIN ITEM_HISTORY WK2
  ON WK1.ITEM_CODE = WK2.ITEM_CODE
 WHERE WK1.USER_UPDATE_DATETIME <> wk2.USER_UPDATE_DATETIME
)
SELECT ITEM_CODE CODE
      ,ITEM_NAME NAME
      ,'ADDED' COMP_RSLT
 FROM T1
UNION
SELECT ITEM_CODE
      ,ITEM_NAME
      ,'DELETED' COMP_RSLT
 FROM T2
UNION
SELECT ITEM_CODE
      ,ITEM_NAME
      ,'UPDATED' COMP_RSLT
 FROM T3
ORDER BY CODE DESC
;