题解 | 淘宝店铺的实际销售额与客单价

SELECT 
    SUM(a.sales_num*b.goods_price) AS sales_total,
    SUM(a.sales_num*b.goods_price)/count(distinct a.user_id) AS per_trans
FROM sales_tb AS a
LEFT JOIN goods_tb AS b
ON a.goods_id=b.goods_id;