SELECT
   COALESCE(i.ITEM_CODE, ih.ITEM_CODE) AS CODE,
   COALESCE(i.ITEM_NAME, ih.ITEM_NAME) AS NAME,
   CASE
       WHEN i.ITEM_CODE IS NULL THEN 'DELETED'
       WHEN ih.ITEM_CODE IS NULL THEN 'ADDED'
       WHEN i.USER_UPDATE_DATETIME <> ih.USER_UPDATE_DATETIME THEN 'UPDATED'
       ELSE NULL
   END AS COMP_RSLT
FROM
   ITEM i
   FULL OUTER JOIN ITEM_HISTORY ih ON i.ITEM_CODE = ih.ITEM_CODE
WHERE
   COALESCE(i.USER_UPDATE_DATETIME, '3000-01-01') <> COALESCE(ih.USER_UPDATE_DATETIME, '1900-01-01')
   OR i.ITEM_CODE IS NULL
   OR ih.ITEM_CODE IS NULL
ORDER BY
   CODE DESC;