使用您确切的数据库表，我获得了一些成功.

I had some success like this, using your exact DB table.

用户模型:

class User extends Eloquent {

    protected $table = 'users';
    public $timestamps = false;

    public function parent()
    {
        return $this->belongsTo('User', 'parent_id');
    }

    public function children()
    {
        return $this->hasMany('User', 'parent_id');
    }

}

然后可以在我的代码中使用它，如下所示:

and then I could use it in my code like this:

$user     = User::find($id);

$parent   = $user->parent()->first();
$children = $user->children()->get();

尝试一下，让我知道你的生活吧！

Give that a try and let me know how you get on!