问mysqli_stmt::bind_param()的参数计数错误

EN

<?php

session_start();

$regValue = $_GET['regName'];

echo "Your registration is: ".$regValue.".";


$servername = "localhost";
$username = "root";
$password = "b4sonic";
$dbname = "b4sonic2";



$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}

// prepare and bind
$stmt = $conn->prepare("INSERT INTO b4sonic (first_name) VALUES (?)");
$stmt->bind_param( $firstname);

// set parameters and execute

$firstname = "John";
$stmt->execute();


echo "New records created successfully";

$stmt->close();
$conn->close();
?>