laravel sum多字段

1、单个字段

 DB::table('table_name')
       ->where('uid',$uid)
       ->sum('likes');

2、多个字段

$post_datas = DB::table('table_name')
      ->where('uid',$uid)
      ->first(
         array(
            \DB::raw('SUM(shares) as shares'),
            \DB::raw('SUM(comments) as comments'),
            \DB::raw('SUM(likes) as likes')
               )
            );