php - MYSQL - 获取用户和最近的购买数据

Question

我正在尝试执行 MYSQL 查询，获取用户最近的购买情况，然后查看是否符合特定条件。这是我整理的查询:

select
    users_purch.purch_date as purchase_date,
    users_purch.total_amount as purchase_amount,
    users.* 
from
    users 
left join
    (
        select
            max(date) as purch_date,
            user_id,
            total_amount 
        from
            users_purchases 
        group by
            user_id
    ) as users_purch 
        on users_purch.user_id = users.id 
where
    users_purch.purch_date < '2016-11-01' 
    and users_purch.total_cost < 112.49 
order by
    users_purch.purch_date desc

查询似乎有效，但在某些方面失败。例如，如果用户有多个购买条目，则它会获取最大日期，但查询检索到的 Total_cost 金额与最大日期不在同一行。如何重写此查询以提供最新的完整购买记录？

谢谢!

Answer 1

您必须再次加入 user_purchases 表才能获取有关日期的信息:

select
    users_purch.purch_date as purchase_date,
    users_purch.total_amount as purchase_amount,
    users.* 
from
    users 
left join
    (
        select
            max(date) as purch_date,
            user_id
        from
            users_purchases 
        group by
            user_id
    ) as users_purch 
        on users_purch.user_id = users.id 
left join
   (
       select
          user_id,
          date,
          total_amount
       from
          users_purchases
   ) as users_purch2 on users_purch.user_id = users_purch2.user_id and
        users_purch2.date = users_purch.purch_date
where
    users_purch.purch_date < '2016-11-01' 
    and users_purch.total_cost < 112.49 
order by
    users_purch.purch_date desc