php - Codeigniter group_by 无法正常工作

Question

我正在尝试从视频表中获取用户 ID 列表。该表包含用户上传的媒体文件。这是我的代码

        $this->db->select("videos.user_id as userId");
        $this->db->limit('10', $document['offset']);
        $this->db->group_by('userId');
        $this->db->order_by('id','desc');

        $recentUploads = $this->db->get('videos')->result_array();
        if (!empty($recentUploads)) 
        {
            foreach ($recentUploads as $record) 
            {
                $totalPostMedia = $obj->totalPostMedia($record);
                $record['totalPostMedia'] = $totalPostMedia;

                $resData = $this->db->select("username, profileImage")->from('users')->where('id', $record['userId'])->get()->row_array();
                $record['uploadBy'] = $resData['username'];
                $record['profileImage'] = "http:...com/profileImage/".$resData['profileImage'];

                $Mydata[] = $record;
            }
        }

获取的结果缺少表中的一些 userId。我也尝试过 $this->db->distinct() 。仍然得到相同的结果。我获得没有重复结果的唯一方法是删除 $this->db->order_by('id','desc'); 或将其设为 asc而不是 desc。但我想从表中获取最新的记录。我该怎么做呢？难道我做错了什么？任何帮助将非常感激。

Answer 1

试试这个

$this->db->select("videos.user_id as userId");
$this->db->from("videos");
$this->db->group_by('userId');
$this->db->order_by('id','desc');
$this->db->limit('10', $document['offset']);

$recentUploads = $this->db->get()->result_array();
if (count($recentUploads)>0) 
{
    foreach ($recentUploads as $record) 
    {
        $totalPostMedia = $obj->totalPostMedia($record);
        $record['totalPostMedia'] = $totalPostMedia;

        $resData = $this->db->select("username, profileImage")->from('users')->where('id', $record['userId'])->get()->row_array();
        $record['uploadBy'] = $resData['username'];
        $record['profileImage'] = "http:...com/profileImage/".$resData['profileImage'];

        $Mydata[] = $record;
    }
}