$qb
            ->orderBy('pc.stock', 'DESC');

        $builder->add('in_stock', 'checkbox', array(
            'required' => false,
            'label' => '在庫ありのみ',
            'value' => 1,
            'empty_data' => null,
        ));

{{ form_widget(form.in_stock) }}

        if ($request->query->get('in_stock') == '1') {
            $qb->andWhere('pc.stock_unlimited = 1 or pc.stock > 0');
        }