select A.ITEM_CODE CODE,
CASE WHEN A.ITEM_NAME <> B.ITEM_NAME THEN  A.ITEM_NAME
     WHEN B.ITEM_NAME = NULL THEN  A.ITEM_NAME
     ELSE NULL 
     END NAME
from ITEM A
left join ITEM_HISTORY B
on A.ITEM_CODE = B.ITEM_CODE
order by A.ITEM_CODE desc