with AVG as(
    select GOODS_CODE ,round(avg(STD_COST_PRICE),0) as AVG
        from SKU
        group by GOODS_CODE
)
, S as (
  select A.goods_code, A.sku_code 
    from sku as A inner join AVG on A.Goods_code = AVG.Goods_code
    where A.STD_COST_PRICE <  AVG.AVG
)
update SKU
    set STD_COST_PRICE = G.STD_COST_PRICE
    from Goods as G inner join S on G.Goods_code = S.Goods_code