简单的php查询验证

<?php
function validateEmail($email) {
    // 使用正则表达式验证电子邮件地址
    if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
        return true;
    } else {
        return false;
    }
}

$email = $_POST['email'];

if (validateEmail($email)) {
    echo "电子邮件地址有效";
} else {
    echo "电子邮件地址无效";
}
?>

<?php
$conn = new mysqli("localhost", "username", "password", "database");

if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

$email = $_POST['email'];

$stmt = $conn->prepare("SELECT * FROM users WHERE email = ?");
$stmt->bind_param("s", $email);

$stmt->execute();
$result = $stmt->get_result();

while ($row = $result->fetch_assoc()) {
    echo "ID: " . $row["id"] . " - Email: " . $row["email"] . "<br>";
}

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