What best practices should be followed when handling form data in PHP to prevent SQL syntax errors?

To prevent SQL syntax errors when handling form data in PHP, it is essential to use prepared statements with parameterized queries. This approach helps to separate SQL logic from user input, preventing malicious SQL injection attacks. By binding parameters to placeholders in the SQL query, you can ensure that the input data is properly sanitized and escaped.

// Establish a database connection
$pdo = new PDO("mysql:host=localhost;dbname=mydatabase", "username", "password");

// Prepare a SQL statement with placeholders
$stmt = $pdo->prepare("INSERT INTO users (username, email) VALUES (:username, :email)");

// Bind parameters to the placeholders
$stmt->bindParam(':username', $_POST['username']);
$stmt->bindParam(':email', $_POST['email']);

// Execute the prepared statement
$stmt->execute();