UPDATE SKU
   SET STD_COST_PRICE = T.STD_COST_PRICE
      ,UPDATE_USER_NAME = 'MODIFY'
      ,USER_UPDATE_DATETIME = '2024-08-31 00:00:00'
  FROM(
        SELECT SKU_CODE
              ,STD_COST_PRICE
          FROM SKU SK
         WHERE STD_COST_PRICE < (
        SELECT ROUND(AVG(STD_COST_PRICE), 0) STD_COST_PRICE
          FROM GOODS G
         GROUP BY G.GOODS_CODE
        HAVING G.GOODS_CODE = SK.GOODS_CODE)
      ) AS T
 WHERE SKU.SKU_CODE = T.SKU_CODE