Question

我有一张包含购买订单数据的表格每行包含购买的特定商品的金额，每件商品的成本和订单号组。购买的每个不同商品都是具有相同订单号的新行。

我基本上想要退回该订单的总费用。我尝试了以下但是无处可去：

SELECT order_number, SUM( sub_total ) AS `total`
FROM
  SELECT order_number, SUM( SUM( amount ) * SUM( cost_per_item ) ) AS `sub_total`
    FROM `ecom_orders`
   WHERE member_id = '4'
GROUP BY order_number
ORDER BY purchase_date DESC

Answer 1

几乎所有符合SQL-92标准的RDBMS都会采用以下方法：

SELECT
order_number
,SUM(amount * cost_per_item) AS total
,purchase_date
FROM
ecom_orders
WHERE member_id = '4'
GROUP BY order_number,purchase_date
ORDER BY purchase_date DESC

从子总数和金额计算总数

1 个答案: