kefu/app/admin/model/Admin.php

<?php

namespace app\admin\model;

use app\BaseModel;
class Admin extends BaseModel
{
    public function role()
{
    return $this->hasOne(Role::class, 'id', 'role_id')->field(['id', 'name']);
}
    public function department()
    {
        return $this->hasOne(Department::class, 'id', 'department_id')->field(['id', 'name']);
    }
}