Laravel code for order Asc and Desc of Custom Filed in Yagra Datatables

    public function query(Customer $model)

        {

        $query = $model->newQuery()

            ->select('*', \DB::raw('(amount1- amount2) as amount'))

            ->where('amount1', '>', 0);          

        // Check if a specific column is being sorted

        if ($this->request()->has('order.0.column')) {

            $columnIndex = $this->request()->input('order.0.column');

            $orderb = $this->request()->input('order.0.dir');

                 

            $column = $this->request()->input("columns.$columnIndex.data");

           

            //If the clicked column is 'amount', order by it; otherwise, no custom ordering

            if ($column !== 'amount') {

                // Reset ordering if clicked on a different column

                $query->orderBy($column, $orderb);

            }else{

                $query->orderBy('amount', $orderb);

            }

        } else {

            // Initial/default ordering

            $query->orderBy('amount', 'desc');

        }

        return $query;

        }