Thanks for your response.

Actually you are right. I do not get what I expect.

In my page.entries I’ve got something like (pseudocode):

posts => [post => [id => 1, title => 'test', 'user_id' => 2, 'comments' => ['user_id' => 2, 'post_id' => 1]]]

I would like to join to each post my favourites from %{"favourite" => Repo.all(Post.getFavourites(x.id, user_id))}

I’m coming from OOP language.
For instance in PHP it would be (again pseudocode):

for ($i = 0; $i < count(page.entries); $i++) {
page.entires[$i]['favourites'] = $this->getFavorite($post_id, $user_id);
}

Probably it is easy, but I can’t get it in elixir.

My purpose is to have information in each post if logged user have post in favourites.

Use left_join maybe?