with avg as(
 SELECT GOODS_CODE,ROUND(AVG(STD_COST_PRICE), 1) as ave
 FROM SKU
 GROUP BY GOODS_CODE
 )

UPDATE  SKU
SET     STD_COST_PRICE = T1.STD_COST_PRICE
FROM    SKU as T
            INNER JOIN GOODS AS T1
                ON T.GOODS_CODE = T1.GOODS_CODE	
WHERE T.STD_COST_PRICE < (
 SELECT ROUND(AVG(STD_COST_PRICE), 1) as ave
 FROM SKU
 GROUP BY GOODS_CODE
 )