如果只是简单关联也可以用 \yii\db\Query
具体查看类手册 \yii\db\Query
比如

$data=(new \yii\db\Query())
                ->select('cf_comment.*,cf_user_wx.nickname,cf_user_wx.headimgurl')
                ->from('cf_comment')
                ->where('time<'.$param['t'])
                ->andWhere(['projectId'=>$param['pjId']])
                ->andWhere(['type'=>1])
                ->leftJoin('cf_user_wx','cf_comment.userId = cf_user_wx.id')
                ->offset($start)
                ->orderBy(['time'=>SORT_DESC])
                ->limit($count)
                ->all();