UPDATE
SKU
SET
STD_COST_PRICE = t3.STD_COST_PRICE
FROM SKU T1
    INNER JOIN (
    SELECT
        GOODS_CODE
        ,ROUND(AVG(STD_COST_PRICE)) AS AVG_STD_COST_PRICE
    FROM SKU
    GROUP BY GOODS_CODE
)t2
    on t1.GOODS_CODE = t2.GOODS_CODE
    INNER JOIN GOODS t3
        on t3.GOODS_CODE = t1.GOODS_CODE
WHERE t2.AVG_STD_COST_PRICE > t1.STD_COST_PRICE