SELECT
T1.ITEM_CODE CODE,
CASE WHEN T1.ITEM_NAME <> T2.ITEM_NAME THEN T1.ITEM_NAME
     WHEN T2.ITEM_NAME IS NULL THEN T1.ITEM_NAME
ELSE "NULL" END AS NAME
FROM ITEM T1
LEFT OUTER JOIN ITEM_HISTORY T2
ON T2.ITEM_CODE = T1.ITEM_CODE
ORDER BY T1.ITEM_CODE DESC