What are some common pitfalls to avoid when working with PHP and MySQL together in a web application?

One common pitfall to avoid when working with PHP and MySQL together in a web application is not properly sanitizing user input before using it in SQL queries. This can lead to SQL injection attacks where malicious users can manipulate your database. To prevent this, always use prepared statements with parameterized queries to securely interact with your database. 

// Connect to MySQL database
$mysqli = new mysqli("localhost", "username", "password", "database");

// Prepare a SQL statement with a parameterized query
$stmt = $mysqli->prepare("SELECT * FROM users WHERE username = ?");
$stmt->bind_param("s", $username);

// Sanitize user input
$username = mysqli_real_escape_string($mysqli, $_POST['username']);

// Execute the query
$stmt->execute();
$result = $stmt->get_result();

// Fetch the results
while ($row = $result->fetch_assoc()) {
    // Do something with the data
}

// Close the statement and connection
$stmt->close();
$mysqli->close();

Keywords

SQL injection PDO prepared statements data validation error handling

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