/* 需要注意在 sum(sales_amount) as total_sales_amount, (sum(sales_amount) - sum(cost_amount)) / sum(sales_amount) as profit_rate 这部分为sum(sales_amount)指定的别名不能为sales_amount,最外层的查询再次指定为sales_amount即可 */ select product_id, product_name, category_id, total_sales_amount as sales_amount, round(profit_rate, 2) a...