What are the implications of using the LIKE operator instead of the = operator in SQL queries for username validation in a PHP login system?

Using the LIKE operator instead of the = operator in SQL queries for username validation in a PHP login system can lead to potential SQL injection vulnerabilities. This is because the LIKE operator allows for pattern matching, which can be exploited by malicious users. To prevent this, it is recommended to use parameterized queries with placeholders to safely handle user input. 

// Using parameterized query with placeholders to validate username
$username = $_POST['username'];

$stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username");
$stmt->bindParam(':username', $username);
$stmt->execute();

if($stmt->rowCount() > 0) {
    // Username exists
    // Proceed with login process
} else {
    // Username does not exist
    // Display error message
}

Keywords

LIKE operator = operator SQL queries username validation PHP login system

Related Questions