Laravel查询构建器 - 多个sum（）问题

Hei there, I'm new in laravel and I have some issues with laravel query builder. The query I would like to build is this one:

Select nofaktur, date, diskon, namacust, SUM(subtotal)+SUM(diskon)) as 
subtot, SUM(diskon) as totaldiskon, total From crLap GROUP BY nofaktur Order
By date, nofaktur.

i've tried like this

$penjualan = DB::table('report_penjualan')
        ->select('nofaktur',
        DB::raw('(SUM(subtotal)+SUM(diskon)) as subtot'), 
        DB::raw('SUM(diskon) as totaldiskon'))
        ->groupBy('nofaktur') 
        ->get()->toArray();

but the field 'date', 'diskon' etc can't be shown..