题解 | 淘宝店铺的实际销售额与客单价

SELECT 
ROUND(SUM(t1.n_sales*t2.goods_price),3) sales_total,
ROUND(SUM(t1.n_sales*t2.goods_price)/AVG(t1.n_users),3) per_trans
FROM(
    SELECT goods_id,SUM(sales_num) n_sales,(SELECT 
    COUNT(DISTINCT user_id)
    FROM sales_tb)  n_users
    FROM sales_tb
    GROUP BY goods_id
) t1
INNER JOIN goods_tb t2
ON t1.goods_id = t2.goods_id