---変更されたデータ
WITH
wk_up(ITEM_CODE)
AS
 (
 SELECT
  a.ITEM_CODE
 FROM
  ITEM a inner join ITEM_HISTORY b
  on a.ITEM_CODE = b.ITEM_CODE
 WHERE
  a.USER_UPDATE_DATETIME <> b.USER_UPDATE_DATETIME
 )
,
---追加
wk_add(ITEM_CODE)
AS
 (
 SELECT
  ITEM_CODE
 FROM
  ITEM
 EXCEPT
 SELECT
  ITEM_CODE
 FROM
  ITEM_HISTORY
 )
,
---削除
wk_del(ITEM_CODE)
AS
 (
 SELECT
  ITEM_CODE
 FROM
  ITEM_HISTORY
 EXCEPT
 SELECT
  ITEM_CODE
 FROM
  ITEM
 )
,
---データまとめ
wk_all(ITEM_CODE, ITEM_NAME, RSLT)
AS
(
 SELECT
 wk_up.ITEM_CODE
 , ITEM.ITEM_NAME
 , 'UPDATED'
 FROM
  wk_up inner join ITEM
  on wk_up.ITEM_CODE = ITEM.ITEM_CODE
 UNION ALL
 SELECT
 wk_add.ITEM_CODE
 , ITEM.ITEM_NAME
 , 'ADDED'
 FROM
  wk_add  inner join ITEM
  on wk_add.ITEM_CODE = ITEM.ITEM_CODE
 UNION ALL
 SELECT
 wk_del.ITEM_CODE
 , ITEM_HISTORY.ITEM_NAME
 , 'DELETED'
 FROM
  wk_del  inner join ITEM_HISTORY
  on wk_del.ITEM_CODE = ITEM_HISTORY.ITEM_CODE
)
----
SELECT
 ITEM_CODE as CODE
 ,ITEM_NAME as NAME
 ,RSLT as COMP_RSLT
FROM
 wk_all
ORDER BY
 CODE desc