How can PHP developers ensure secure data handling when implementing user-specific filters in SQL queries?

PHP developers can ensure secure data handling when implementing user-specific filters in SQL queries by using prepared statements with parameterized queries. This approach helps prevent SQL injection attacks by separating SQL logic from user input. By binding user input as parameters in the query, developers can safely execute dynamic SQL queries without risking the integrity of the database. 

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

// User input
$user_input = $_GET['user_input'];

// Prepare SQL query with parameterized query
$stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username");
$stmt->bindParam(':username', $user_input, PDO::PARAM_STR);
$stmt->execute();

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

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

Keywords

PHP data handling user-specific filters SQL queries secure.

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