SELECT
  R.CODE,
  R.NAME,
  R.COMP_RSLT
FROM
(SELECT
  IFNULL(i.ITEM_CODE,h.ITEM_CODE) AS CODE,
  IFNULL(i.ITEM_NAME,h.ITEM_NAME) AS NAME,
  CASE
    WHEN h.ITEM_CODE IS NULL THEN 'ADDED'
    WHEN i.ITEM_CODE IS NULL THEN 'DELETED'
    WHEN i.USER_UPDATE_DATETIME <> h.USER_UPDATE_DATETIME THEN 'UPDATED'
    ELSE NULL  
  END AS COMP_RSLT
FROM ITEM i FULL OUTER JOIN ITEM_HISTORY h ON i.ITEM_CODE = h.ITEM_CODE
ORDER BY CODE DESC) R
WHERE R.COMP_RSLT IS NOT NULL