yuanchengpasc/application/manage/model/DeviceModel.php

<?php
namespace app\manage\model;

use think\Model;
use think\Db;

class DeviceModel extends Model {
    protected $table = 'device';

    public function queryAll($institutionId){
        $query = Db::view('device','id,name,exam_class_id,status')
            ->view('exam_class', 'name as ecName', 'device.exam_class_id=exam_class.id')
            ->view('institution', 'name as institutionName', 'exam_class.institution_id=institution.id');
        if ($institutionId){
            $query->where('institution.id', $institutionId);
        }
        return $query->select();
    }

    public function queryOne($id){
        $query = Db::view('device','id,name,exam_class_id,status')
            ->view('exam_class', 'name as ecName', 'device.exam_class_id=exam_class.id')
            ->view('institution', 'name as institutionName, id as insId', 'exam_class.institution_id=institution.id')
            ->where('device.id', $id);
        return $query->find();
    }
}