Laravel Eloquent: sum with groupBy

Document::groupBy('users_editor_id')
   ->selectRaw('sum(no_of_pages) as sum, users_editor_id')
   ->pluck('sum','users_editor_id');

   // originally lists(), which was deprecated in favour of pluck in 5.2
   // and dropped completely in 5.3
   // ->lists('sum','users_editor_id');


// returns array like this:
array(
  users_editor_id => sum,
  ...
)

Or this way (which I wouldn't use, since it won't be actual ORM result):

Document::groupBy('users_editor_id')
   ->selectRaw('*, sum(no_of_pages) as sum')
   ->get();

// returns collection of Document pseudo models with additional sum field

Document::Where('some_condition',true)
   ->select([DB::raw("SUM(debit) as total_debit"), DB::raw("SUM(credit) as total_credit")])
   ->groupBy('id')
   ->get()

Little bit refactored and convenient answer is (from @keroles Monsef)

Document::Where('some_condition',true)
    ->selectRaw("SUM(debit) as total_debit")
    ->selectRaw("SUM(credit) as total_credit")
    ->groupBy('id')
    ->get();