SELECT
 COALESCE(H.ITEM_CODE, I.ITEM_CODE) AS CODE
,COALESCE(H.ITEM_NAME, I.ITEM_NAME) AS NAME
-- 追加された場合は「ADDED」、更新された場合は「UPDATED」、削除された場合は「DELETED」
,CASE
 WHEN H.ITEM_CODE IS NULL THEN 'ADDED'
 WHEN H.USER_UPDATE_DATETIME <> I.USER_UPDATE_DATETIME THEN 'UPDATED'
 WHEN I.ITEM_CODE IS NULL THEN 'DELETED'
 END AS COMP_RSLT
FROM ITEM_HISTORY AS H
FULL OUTER JOIN ITEM AS I
ON H.ITEM_CODE = I.ITEM_CODE
WHERE COMP_RSLT IS NOT NULL
-- 表示項目CODEの降順
ORDER BY CODE DESC
;