SELECT
I.ITEM_CODE AS CODE,
CASE
  WHEN IH.ITEM_NAME IS  NULL THEN I.ITEM_NAME
  WHEN I.ITEM_NAME <> IH.ITEM_NAME THEN I.ITEM_NAME
  ELSE NULL
END
AS NAME
FROM ITEM I
LEFT JOIN ITEM_HISTORY IH
ON I.ITEM_CODE =  IH.ITEM_CODE
ORDER BY I.ITEM_CODE desc