mysql 使用 LEFT JOIN 按天分组结果

Question

当有人购买商品时，我有付款表，我添加了 1 条记录，其中包含金额和日期

一些买家需要额外的物品服务（运输支持......） 所以我有服务表，其中包含服务价格和 payment_id

我想要这样的结果

   date    -  Sum(payments)  -  Sum(services)
01-01-2016 -    200          -       100
02-01-2016 -    200          -       100
03-01-2016 -    100          -        0

我试过这个查询

SELECT DATE(FROM_UNIXTIME(date)),SUM(amount),SUM(price) 
FROM payments 
LEFT JOIN services ON payments.id = service.payment_id 
GROUP BY DATE(FROM_UNIXTIME(date))

但返回重复值 提前谢谢

Answer 1

您需要使用一个子查询来连接这两个表并对每次付款的价格求和。然后您可以按日期对该结果进行分组。

SELECT date, SUM(payments), SUM(services)
FROM (
    SELECT DATE(FROM_UNIXTIME(p.date)) AS date, p.amount AS payments, IFNULL(SUM(s.price), 0) AS services
    FROM payments AS p
    LEFT JOIN services AS s ON p.id = s.payment_id
    GROUP BY p.id
) AS subquery
GROUP BY date