huahuibao/app/admin/controllers/PictureController.php

<?php
namespace backend\controllers;
use common\models\xhTrainStudent;

use Yii;
use yii\web\Controller;
use yii\filters\AccessControl;
use yii\data\Pagination;

/**
 * student controller
 */
class PictureController extends BackendController
{

    public function actionList()
    {
        $query = xhTrainStudent::find();
        $query->where(['merchantId' => $this->merchantId]);
        $query->orderBy('id desc');
        $countQuery = clone $query;
        $pages = new Pagination(['totalCount' => $countQuery->count(), 'pageSize' => 20]);
        $models = $query->offset($pages->offset)->limit($pages->limit)->all();
        return $this->render('list', ['models' => $models, 'pages' => $pages]);
    }

}