Laravel多对多/从db中选择与另一个不相关的条目

Question

I am trying to fetch items from my laravel many to many relationship.

I have posts and tags.

So there is the possibility that there are tags that are not yet connected to a post. How can I get those from the DB?

$tags = Tag::with('posts')->where('posts', [])->get();
$tags = Tag::with('posts')->where('posts', '')->get();
$tags = Tag::with('posts')->wherePosts('')->get();
$tags = Tag::with('posts')->wherePosts([])->get();

Those do not work. Is there any other way? If I return

$tags = Tag::with('posts')->get();

I can see those where posts = [] but I dont now how to fetch them.

Thanks.

Answer 1

Use querying relations:

$tags = Tag::has('posts', '=', 0)->get();

http://laravel.com/docs/eloquent#many-to-many