with sum laravel code example

Example 1: select sum in laravel

Sometime for such queries you need to disable the strict check
 So inside config/database.php and inside mysql, 
 Set 'strict' => false,

->select('user_id', DB::raw('SUM(points) as total_points'))

Example 2: laravel eloquent sum column

Product::where('id',$id)->sum('quantity');

Example 3: sum row data and get all data eloquent laravel

$balance = DB::table('data')->where('user_id' '=' $id)->sum('balance');

Example 4: laravel sum column values

Auth::user()->products->sum('price');
// And on your App/User.php you need someting like this:
public function products(){
  return Products::where('id_buyer', Auth::user()->id)->get();
}