请问一下我这个跨库联表查询为什么报错了呢？ [ 2.0 版本 ]

Database Exception – yii\db\Exception
SQLSTATE[42000]: Syntax error or access violation: 1142 SELECT command denied to user
public function  actionSearch(){
        $results = (new Query())->select([
            'al.al_id',
            'al.al_add_user_id',
            'al.al_title',
            'al.al_thumb',
            'al.desc',
            'al.al_post_time',
            'al.transport_name',
            'u.user_name'
        ])
            ->from('article_list as al')
            ->leftJoin('Yii::$app->db_user.user as u','al.al_add_user_id = u.user_id')
            ->All(Yii::$app->db_home);
        print_r($results);die;
    }