Laravel PHP :当我们在3个表上应用连接时，如何获取特定的列ID？

public function posts()
{
    return $this->hasMany(Post::class);
}

public function comments()
{
    return $this->hasMany(Comment::class);
}

$users = User::with(['posts' => function ($query) {
    $query->with(['comments' => function ($query) {
        $query->select('id');
    }]);
}])->get();

$user = User::with(['posts' => function ($query) use ($postId) {
    $query->where('id', $postId)->with(['comments' => function ($query) use ($commentId) {
        $query->where('id', $commentId)->select('id');
    }]);
}])->find($userId);