laravel-5

Eloquent: Relationships 595
Counting Relationship Results
If you want to count the number of results from a relationship without actually loading them you
may use the withCount method, which will place a {relation}_count column on your resulting
models. For example:
1 $posts = App\Post::withCount('comments')->get();
2
3 foreach ($posts as $post) {
4 echo $post->comments_count;
5 }
You may add retrieve the “counts” for multiple relations as well as add constraints to the queries:
1 $posts = Post::withCount(['votes', 'comments' => function ($query) {
2 $query->where('content', 'like', 'foo%');
3 }])->get();
4
5 echo $posts[0]->votes_count;
6 echo $posts[0]->comments_count;
Eager Loading
When accessing Eloquent relationships as properties, the relationship data is “lazy loaded”. This
means the relationship data is not actually loaded until you first access the property. However,
Eloquent can “eager load” relationships at the time you query the parent model. Eager loading
alleviates the N + 1 query problem. To illustrate the N + 1 query problem, consider a Book model
that is related to Author:
1