SELECT
item.ITEM_CODE AS CODE,
CASE
 WHEN history.ITEM_CODE IS NULL THEN item.ITEM_NAME
 WHEN item.ITEM_NAME != history.ITEM_CODE THEN item.ITEM_NAME
 ELSE NULL
END AS NAME
FROM ITEM item LEFT OUTER JOIN ITEM_HISTORY history ON item.ITEM_CODE = history.ITEM_CODE
ORDER BY item.ITEM_CODE DESC