What precautions should be taken when passing database query parts through GET or POST requests in PHP?

When passing database query parts through GET or POST requests in PHP, it is important to sanitize and validate the input to prevent SQL injection attacks. This can be done by using prepared statements with parameterized queries or by using functions like mysqli_real_escape_string to escape special characters. 

// Example of using prepared statements with parameterized queries
$mysqli = new mysqli("localhost", "username", "password", "database");

$query = "SELECT * FROM users WHERE username = ?";
$stmt = $mysqli->prepare($query);
$stmt->bind_param("s", $_POST['username']);
$stmt->execute();

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

$stmt->close();
$mysqli->close();

Keywords

SQL injection prepared statements PDO mysqli_real_escape_string parameterized queries

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