多个左连接已影响到我的SUM（TIMESTAMPDIFF计算

Question

我目前正在尝试创建一个报表，总计有一些个人在我的PHPBB3论坛上的时间总数已经预订了，最后一周。下面的查询和预期一样：

SELECT forum_users.username, SUM(TIMESTAMPDIFF(SECOND, schedule_slots.time_starting, schedule_slots.time_finishing)) AS seconds 
FROM forum_users 
LEFT JOIN schedule_slots 
    ON forum_users.user_id = schedule_slots.user_id 
    AND schedule_slots.time_starting >= (CURDATE() - INTERVAL 1 WEEK) 
    AND schedule_slots.is_del = 0 
    AND schedule_slots.channel = 0 
WHERE (forum_users.group_id = 8 OR forum_users.group_id = 5 OR forum_users.group_id = 14) 
GROUP BY forum_users.username 
ORDER BY upper(forum_users.username) 

然而，当我去参加另一个表，时间戳差异最终被错误地计算（这是更高），这是我的新的非工作声明：

SELECT forum_users.username, SUM(TIMESTAMPDIFF(SECOND, schedule_slots.time_starting, schedule_slots.time_finishing)) AS seconds, group_concat(DISTINCT forum_user_group.group_id) AS user_groups 
FROM forum_users 
LEFT JOIN schedule_slots 
    ON forum_users.user_id = schedule_slots.user_id 
    AND schedule_slots.time_starting >= (CURDATE() - INTERVAL 1 WEEK) 
    AND schedule_slots.is_del = 0 
    AND schedule_slots.channel = 0 
LEFT JOIN forum_user_group 
    ON forum_user_group.user_id = forum_users.user_id 
WHERE (forum_users.group_id = 8 OR forum_users.group_id = 5 OR forum_users.group_id = 14 OR forum_users.group_id = 12) 
GROUP BY forum_users.username 
ORDER BY upper(forum_users.username) 

我在这一张上画了一张空白，非常感谢你的帮助。

Answer 1

时间戳差值的权利，但您可以通过组，用户可以在数乘以

我会尝试：

SELECT forum_users.username, SUM(TIMESTAMPDIFF(SECOND, schedule_slots.time_starting, schedule_slots.time_finishing)) AS seconds, 
(select group_concat(DISTINCT group_id) from forum_user_group WHERE forum_user_group.user_id = forum_users.user_id) AS user_groups 
FROM forum_users 
LEFT JOIN schedule_slots 
ON forum_users.user_id = schedule_slots.user_id 
AND schedule_slots.time_starting >= (CURDATE() - INTERVAL 1 WEEK) 
AND schedule_slots.is_del = 0 
AND schedule_slots.channel = 0 
WHERE (forum_users.group_id = 8 OR forum_users.group_id = 5 OR forum_users.group_id = 14 OR forum_users.group_id = 12) 
GROUP BY forum_users.username, user_groups 
ORDER BY upper(forum_users.username)