对两个不同表中的 SQL 值组合并使用算术

1. 我有一个表格，其中包含活动客人的数据。我可以通过以下查询检索参加（membersAttended

   ）的人数：

   SELECT COUNT(DISTINCT g.`name1`) AS `membersAttended`
       FROM `tmc_doorapp_guests` g
       LEFT JOIN `tmc_doorapp_events` e
       ON e.`id` = g.`event_id`
       WHERE `name1` REGEXP '^[0-9]+$'
       AND e.`date` > DATE_SUB(NOW(), INTERVAL 30 DAY)
       AND g.`checkin` = 1;
   

2. 要检索成员总数（totalMembers），我使用：

   SELECT COUNT(DISTINCT `id`) AS `totalMembers`
       FROM `tmc_users`;
   

3. 为了获得参加过的成员总数的百分比值（totalPercent），我使用 PHP 进行两个查询，然后按如下方式计算：

   $totalPercent = number_format(($membersAttended/$totalMembers*100),2);
   

我尝试以类似于下面的方式组合这两个查询和百分比计算，但没有运气：

    SELECT COUNT(DISTINCT g.`name1`) AS `membersAttended`,
        COUNT(DISTINCT m.`id`) AS `totalMembers`,
        (`membersAttended` * 100 / `totalMembers`) AS `totalPercent`
        FROM `tmc_doorapp_guests` g, `tmc_users` m
        LEFT JOIN `tmc_doorapp_events` e
        ON e.`id` = g.`event_id`
        WHERE `name1` REGEXP '^[0-9]+$'
        AND e.`date` > DATE_SUB(NOW(), INTERVAL 30 DAY)
        AND g.`checkin` = 1;

我还尝试扩展列：

    SELECT COUNT(DISTINCT g.`name1`) AS `membersAttended`,
        COUNT(DISTINCT m.`id`) AS `totalMembers`,
        (COUNT(DISTINCT g.`name1`) * 100 / COUNT(DISTINCT m.`id`)) AS `totalPercent`
        FROM `tmc_doorapp_guests` g, `tmc_users` m
        LEFT JOIN `tmc_doorapp_events` e
        ON e.`id` = g.`event_id`
        WHERE `name1` REGEXP '^[0-9]+$'
        AND e.`date` > DATE_SUB(NOW(), INTERVAL 30 DAY)
        AND g.`checkin` = 1;

这给了我错误：

错误代码：1054。"on 子句"中的未知列"g.event_id"

如何将这些 SQL/PHP 查询/计算合并到一个 SQL 查询中？