1. 假设有个用户级别 Level, 现在要显示 vip 级别的文章，总涉及到 Level,User,Post 三个 model.

User 做为中间层。

<?PHP

namespace App;

use Illuminate\Database\Eloquent\Model;

class Level extends Model
{public function posts ()
    {return $this->hasManyThrough (Post::class, User::class);
    }
}

2. 测试代码，与多对多类似 Level::with ("posts")->first ();