What are some potential pitfalls of using dynamic variables in SQL queries, as seen in the forum thread?

Using dynamic variables in SQL queries can lead to SQL injection attacks if the input is not properly sanitized. To prevent this, it is recommended to use prepared statements with parameterized queries, which separate the SQL code from the user input. 

// Example of using prepared statements to prevent SQL injection
$pdo = new PDO("mysql:host=localhost;dbname=mydatabase", "username", "password");

// User input
$userInput = $_POST['user_input'];

// Prepare a SQL statement with a placeholder
$stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username");

// Bind the user input to the placeholder
$stmt->bindParam(':username', $userInput);

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

// Fetch the results
$results = $stmt->fetchAll(PDO::FETCH_ASSOC);

// Display the results
foreach ($results as $row) {
    echo $row['username'] . "<br>";
}

Keywords

dynamic variables SQL injection prepared statements security vulnerability data sanitization

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