SQL变量在MariaDB中不起作用

Question

在我的查询中，我需要使用当前行获取上一行，然后加入几个表。我在我的开发服务器（MySQL 5.7）中使用SQL变量获得了前一行，一切正常，但在我的生产（MariaDB 10）服务器中，前一行结果不好只是混合，坏部分只是前一行有SQL变量其他查询部分效果很好。

我的查询：

                                  customers.title,
                                  calendar.start_time, 
                                  calendar.hours_per_time,
                                  calendar.self_certification,
                                  calendar.bulletin_certification,
                                  calendar.extra,
                                  @previous_start AS previous_start,
                                  @previous_start := calendar.start_time,
                                  @previous_end AS previous_end,
                                  @previous_end := calendar.hours_per_time,
                                  DATE_FORMAT(calendar.date, '%d-%m') AS day_month,
                                  TIME_FORMAT(calendar.start_time, '%H:%i') AS hours_min

        FROM
          (SELECT @previous_start := '00:00', @previous_end := '0.00') AS calendar_prev, calendar

            INNER JOIN relationships ON calendar.relation_id = relationships.relation_id
            INNER JOIN customers ON customers.customer_id = relationships.customer_id
            WHERE relationships.user_id = '$user_id'
            AND DATE_FORMAT(calendar.date, '%m-%Y') = '$date'
        ORDER BY calendar.date, hours_min ASC