Php “左联接代码监视器”中出错；“非唯一表/别名”；

我有一个错误，它说

不是唯一的表/别名：“pcdom\u传教士”

这是我在模型中的示例代码

public function samplemethodname()
    {
        $this->db->select('companionship_id, missionary_one_id, missionary_two_id, missionary_three_id, pcdom_companionship.zone_id AS pczone_id, pcdom_companionship.district_id AS pcdistrict_id,
            pcdom_companionship.area_id AS pcarea_id, assignment, zone_name, pcdom_zone.zone_id AS pz_zone_id, district_name, pcdom_district.district_id AS pd_district_id, area_name, pcdom_area.area_id AS pa_area_id, missionary_id, missionaries_name')
                ->from('pcdom_companionship')
                ->join('pcdom_missionaries','pcdom_missionaries.missionary_id = pcdom_companionship.missionary_one_id','left')
                ->join('pcdom_missionaries','pcdom_missionaries.missionary_id = pcdom_companionship.missionary_two_id','left')
                ->join('pcdom_missionaries','pcdom_missionaries.missionary_id = pcdom_companionship.missionary_three_id','left')
                ->join('pcdom_zone','pcdom_zone.zone_id = pcdom_companionship.zone_id','left')
                ->join('pcdom_district','pcdom_district.district_id = pcdom_companionship.district_id','left')
                ->join('pcdom_area','pcdom_area.area_id = pcdom_companionship.area_id','left');
                $sql = $this->db->get();
                if($sql && $sql->num_rows() > 0 )
                    return $sql->result();
                else
                    return;
    }

图像中出现错误

有人有这个想法吗？

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提前感谢

因为您正在对

pcdom\u传教士

执行自联接，所以需要在每个单独的联接中别名

pcdom\u传教士

表，使其看起来对SQL来说是唯一的，以便它可以在联接中使用而不会混淆

->join('pcdom_missionaries as pcdom_m1','pcdom_m1.missionary_id = pcdom_companionship.missionary_one_id','left')
->join('pcdom_missionaries as pcdom_m2','pcdom_m2.missionary_id = pcdom_companionship.missionary_two_id','left')
->join('pcdom_missionaries as pcdom_m3','pcdom_m3.missionary_id = pcdom_companionship.missionary_three_id','left')

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我可以在连接中放入数组吗？很抱歉，我没有得到，你是说数组作为连接条件吗？或者你是说？是的，就是这样。。连接条件内的数组。。好吧，你回答我的问题。。谢谢