如何过滤first_name，然后在PHP PDO中搜索唯一的first_name？

SELECT * FROM users WHERE first_name = :first_name

$dsn = "mysql:host=localhost;dbname=your_database";
$username = "your_username";
$password = "your_password";

try {
    $pdo = new PDO($dsn, $username, $password);
} catch (PDOException $e) {
    echo "Connection failed: " . $e->getMessage();
    exit;
}

$sql = "SELECT * FROM users WHERE first_name = :first_name";

$first_name = "John"; // 要过滤的first_name值

$stmt = $pdo->prepare($sql);
$stmt->bindParam(':first_name', $first_name, PDO::PARAM_STR);
$stmt->execute();

$result = $stmt->fetch(PDO::FETCH_ASSOC);

if ($result) {
    // 处理查询结果
    echo "First name found: " . $result['first_name'];
} else {
    echo "First name not found.";
}