Saving Order Details to Custom WordPress Table

add_action('woocommerce_payment_complete', 'action_payment_complete', 30, 1);

function action_payment_complete($order_id) {
    global $wpdb, $current_user;
    $order = wc_get_order($order_id);
    foreach ($order->get_items() as $item) {
        $_product = apply_filters('woocommerce_order_item_product', $order->get_product_from_item($item), $item);
        $item_meta = new WC_Order_Item_Meta($item['item_meta'], $_product);
        $p_name = $_product->name . ' Purchased';
        $add_activity = $wpdb->query("INSERT INTO `user_activity_log`(`activity_name`, `user_id`) VALUES ('$p_name', '$current_user->ID')");
    }
}