根据MySQL中的数量获取SUM？

Question

我有这张桌子

订单

• orders_id
• order_article_id
• order_invoice_id
• order_customer_id
• order_qty

制品

• articles_id
• article_name
• article_qty
• article_price
• article_amount

客户

• customers_id
• customer_name
• customer_position
• customer_office

和SQL Join Table

$sql="SELECT customer_name, article_name, orders_id FROM orders  
            LEFT JOIN articles ON order_article_id = articles_id 
            LEFT JOIN customers  on order_customer_id = customers_id";

从这个查询我需要获得AMOUNT。 数量是示例

USER：MICHAEL

AMOUNT：订单ID = order_article_id + order_qty;

是否可以在MySQL中执行此操作，或者我需要一些额外的PHP代码？

Answer 1

您可以使用GROUP BY查询和SUM（）聚合函数在MySQL中执行此操作：

SELECT
  c.customer_name,
  SUM(a.article_price*a.article_quantity) AS amount
FROM
  orders o LEFT JOIN articles a
  ON o.order_article_id = a.articles_id 
  LEFT JOIN customers c
  ON o.order_customer_id = c.customers_id
GROUP BY
  c.customers_id,
  c.customer_name

您可能希望获得每个订单的AMOUNT，然后您还需要为order_id分组：

GROUP BY
  o.orders_id,
  c.customers_id,
  c.customer_name