Laravel sortBy paginate

Question

I have a posts table and comments table, comment belongs to post, and I have the relationship setup in Post and Comment model. I did sort posts by the numb

Answer 1

This sounds obvious, but Eloquent will not return a result set here, but rather it will return a collection.

If you dig into the source (Builder::get calls Builder::getFresh, which calls Builder::runSelect, which calls Connection::select), you'll find that it's intention is to simply return the results, which are then placed into a collection (which has the sortBy method).

/**
 * Run a select statement against the database.
 *
 * @param  string  $query
 * @param  array  $bindings
 * @param  bool  $useReadPdo
 * @return array
 */
public function select($query, $bindings = array(), $useReadPdo = true)
{
  return $this->run($query, $bindings, function($me, $query, $bindings) use ($useReadPdo)
  {    
    if ($me->pretending()) return array();

    // For select statements, we'll simply execute the query and return an array
    // of the database result set. Each element in the array will be a single
    // row from the database table, and will either be an array or objects.
    $statement = $this->getPdoForSelect($useReadPdo)->prepare($query);

    $statement->execute($me->prepareBindings($bindings));

    //** this is a very basic form of fetching, it is limited to the PDO consts.
    return $statement->fetchAll($me->getFetchMode());
  });  
}

If you want to have pagination without loading every item, then you need to use @Marcin's solution (duplicated below):

$posts = Post::leftJoin('comments','posts.id','=','comments.post_id')->
           selectRaw('posts.*, count(comments.post_id) AS `count`')->
           groupBy('posts.id')->
           orderBy('count','DESC')->
           skip(0)->take(20)->get();