Laravel join 3 tables and get the SUM

I have 3 tables which are orders, commissions and order_items. Below is the table structures

Orders

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Commissions

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Order Items

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I want to get Totla commissions, and Total amount using joins.

  • Total amount is giving correct figure
  • Total commssions is not

How I know this is by getting the data separately by using one join (which works correctly), but using 2 joins does not.

Getting total commissions only (Gives correct values)

$getstats = Order::select(
                DB::raw('SUM(sc.amount) as totalcommissions')
            )
            ->leftJoin('commissions as sc', 'sc.order_id', '=', 'orders.id')
            ->first();

Getting both total commissions and total amount (wrong values)

$getstats = Order::select(
                DB::raw('SUM(sc.amount) as totalcommissions'),
                DB::raw('SUM(oi.qty * oi.each) as totalamount')
            )
            ->leftJoin('order_items as oi', 'oi.order_id', '=', 'orders.id')
            ->leftJoin('commissions as sc', 'sc.order_id', '=', 'orders.id')
            ->first();

Does not give correct values.

Where am I going wrong.