What are some common pitfalls to avoid when using MySQL queries in PHP code?

One common pitfall to avoid when using MySQL queries in PHP code is SQL injection attacks. To prevent this, always use prepared statements with parameterized queries instead of directly inserting user input into the query. This ensures that user input is treated as data rather than executable SQL code. 

// Using prepared statements to prevent SQL injection

// Establish a database connection
$mysqli = new mysqli("localhost", "username", "password", "database");

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

// Set the value of the parameter and execute the query
$username = $_POST['username'];
$stmt->execute();

// Fetch the results
$result = $stmt->get_result();
while ($row = $result->fetch_assoc()) {
    // Process the data
}

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

Keywords

MySQL queries PHP code SQL injection error handling data validation

Related Questions