mark/application/admin/model/AuthGroupAccess.php

<?php

namespace app\admin\model;

use think\Model;

class AuthGroupAccess extends Model
{

    /**
     * 获取所属组名
     * @param $usr_id
     * @return bool|mixed
     */
    public static function getGroupName($usr_id)
    {
        $name = self::where('uid',$usr_id)
            ->alias('a')
            ->join(['auth_group'=>'g'],'a.uid')
            ->value('g.name');
        if($name){
            return $name;
        }

        return false;
    }
}