1.表格meeting

型号名称CoreMeeting
字段id, title, start time, created_by
关系：

'MeetingParticipants' => array(self::HAS_MANY, 'MeetingParticipants', 'meeting_id'),

2.表格core_meeting_participant

型号名称为meeting_participant
字段为id, meeting_id, participant_id, group_id
关系：

'meeting' => array(self::BELONGS_TO, 'CoreMeeting', 'meeting_id'),
 'group' => array(self::BELONGS_TO, 'MeetingGroup', 'group_id'),

3.表格core_meeting_group

型号名称为MeetingGroup
字段为id, group_name
我在会议模型中的搜索筛选器是：

public function search()
{

    $group=filter_var($_REQUEST['group'], FILTER_SANITIZE_STRING);//contain group name

    $criteria=new CDbCriteria;
    $user_id = Yii::app()->user->id;

    $criteria->compare('id',$this->id);
    $criteria->compare('title',$this->title,true);
    $criteria->with=array('MeetingParticipants'=>array("select"=>"*"),'MeetingParticipants.group'=>array('select'=>'id,group_name'));

    if(isset($this->start_time) && !empty($this->start_time))
    $criteria->compare('start_time',date("Y-m-d", strtotime($this->start_time)), true);

    $criteria->compare('created_by',$user_id);

    if(isset($group)&&!empty($group))
    $criteria->compare('group.group_name',$group);
    $criteria->together = true;

    return new CActiveDataProvider($this, array(
        'criteria'=>$criteria,

    ));
}

我已经创建了4个会议，每个会议至少有5个参与者，每个参与者都属于一个会议组.我希望列出所有会议，并在下面列出会议标题，组与会议时间.
我的问题是，如果启用$criteria->together = true;，会议的参与者超过10人，则在网格视图中仅显示1个会议。如果禁用此选项，则将显示所有会议，但无法使用会议名称进行搜索。SQL fiddle链接为http：//sqlfiddle.com/#！9/fdaacf full SQL dump https://pastebin.com/NtpMuCpE