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