SELECT ITEM.ITEM_CODE CODE, 
       CASE
        WHEN OLD.ITEM_NAME IS NULL THEN ITEM.ITEM_NAME
        WHEN ITEM.ITEM_NAME <> OLD.ITEM_NAME THEN ITEM.ITEM_NAME
        WHEN ITEM.ITEM_NAME = OLD.ITEM_NAME THEN NULL
       END NAME
FROM ITEM LEFT OUTER join ITEM_HISTORY OLD on (ITEM.ITEM_CODE = OLD.ITEM_CODE)
ORDER BY 1 DESC