好您可以为原始订单和克隆订单添加元数据。每次克隆项目时，只需为其添加+1即可。

function create_order( $original_order_id, ...
    try {
            $new_order = new WC_Order();
            $new_order->set_props( array( ...
    }

    $original_order = wc_get_order( $original_order_id );
    $order_item_num = $original_order->get_meta(\'_order_items_num\');
    if($order_item_num >= 1) {
        $new_order->update_meta_data( \'_order_item_num\', $order_item_num+1 );
        $new_order->save();
        $original_order->update_meta_data( \'_order_items_num\', $order_item_num+1 );
        $original_order->save();
    } else {
        $new_order->update_meta_data( \'_order_item_num\', \'1\' );
        $new_order->save();
        $original_order->update_meta_data( \'_order_items_num\', \'1\' );
        $original_order->save();
    }

add_filter( \'woocommerce_order_number\', \'change_woocommerce_order_number\', 1, 2);
function change_woocommerce_order_number( $order_id, $order ) {
    $parent_id = $order->parent_id;
    if($parent_id != 0) {
        $parent_order = wc_get_order( $parent_id );
        $order_sub_num = $order->get_meta(\'_order_item_num\');
        return $parent_id . \'-\' . $order_sub_num;
    }
    return $order->id;
}