PHP Propel ORM MySQL - 多对多的左连接

Question

我有两张表，一张称为会议，一张称为出勤，出勤是一个多对多关系数据库，格式如下：

Attendance:
    user_id | meeting_id | invited
    --------+------------+--------
    1       | 5          | 1
    2       | 5          | 0
    3       | 4          | 0
    3       | 5          | 1
    3       | 6          | 0

会议采用以下格式：

Meetings:
    meeting_id | meeting_name | owner_id
    -----------+--------------+----------
    3          | Awesome      | 2
    4          | Boring       | 2
    5          | Cool         | 5
    9          | Sexy         | 3

每个会议只能有一个会议行，但每个会议的出席行数不受限制（有限）每次会议的每个可能的用户）。

如何在 SQL 和/或 Propel 中创建一些内容来列出所有会议，其中（提供的）用户 ID 是会议中的所有者 ID，或者是出席数据库中的用户 ID 和受邀者。

我在搜索 userid 3 时正在寻找结果（基于上述数据）：

Result for userid3:
    meeting_id | meeting_name | owner_id
    -----------+--------------+----------
    5          | Cool         | 5     - Because userid 3 is attending meeting 5
    9          | Sexy         | 3     - Because userid 3 owns meeting 9

我目前有以下内容，但实际上并不起作用，并且每个会议产生多行（因为该会议在出席数据库中存在不止一次） ）。

$criteria->addJoin(MeetingMeetingsPeer::ID, MeetingAttendancePeer::MEETING_ID, Criteria::LEFT_JOIN);

$criterion = $criteria->getNewCriterion(MeetingMeetingsPeer::OWNER_ID, Meeting::getUserId());
$criterion->addOr($criteria->getNewCriterion(MeetingAttendancePeer::USER_ID, Meeting::getUserId()));

$criteria->add($criterion); 
return $criteria;

SQL 如下所示：

SELECT meeting_meetings.ID, meeting_meetings.OWNER_ID, meeting_meetings.GROUP_ID, meeting_meetings.NAME, meeting_meetings.COMPLETED, meeting_meetings.LOCATION, meeting_meetings.START, meeting_meetings.LENGTH, meeting_meetings.CREATED_AT, meeting_meetings.UPDATED_AT FROM `meeting_meetings` LEFT JOIN meeting_attendance ON (meeting_meetings.ID=meeting_attendance.MEETING_ID) WHERE (meeting_meetings.OWNER_ID=1 OR meeting_attendance.USER_ID=1) 

感谢您的宝贵时间，

Answer 1

这应该会获得 user_id 1 拥有的所有会议，以及 user_id 1 参加的所有会议。

SELECT meeting_meetings.ID, meeting_meetings.OWNER_ID, meeting_meetings.GROUP_ID, meeting_meetings.NAME, 
meeting_meetings.COMPLETED, meeting_meetings.LOCATION, meeting_meetings.START, meeting_meetings.LENGTH, 
meeting_meetings.CREATED_AT, meeting_meetings.UPDATED_AT 
FROM `meeting_meetings`
WHERE `meeting_meetings`.`owner_id` = 1
UNION DISTINCT
SELECT meeting_meetings.ID, meeting_meetings.OWNER_ID, meeting_meetings.GROUP_ID, meeting_meetings.NAME, 
meeting_meetings.COMPLETED, meeting_meetings.LOCATION, meeting_meetings.START, meeting_meetings.LENGTH, 
meeting_meetings.CREATED_AT, meeting_meetings.UPDATED_AT 
FROM `meeting_meetings`
JOIN `meeting_attendance` ON `meeting_meetings`.`meeting_id` = `meeting_attendance`.`meeting_id` AND `meeting_attendance`.`invited`
WHERE `meeting_attendance`.`user_id` = 1

这有点笨拙。就我个人而言，我会考虑向 meetings_attendance 表添加一个 owner 标志。