What are some common mistakes to avoid when handling select boxes and database queries in PHP?

One common mistake when handling select boxes and database queries in PHP is not sanitizing user input before using it in a query, which can lead to SQL injection attacks. To avoid this, always use prepared statements or parameterized queries when interacting with the database. 

// Example of using prepared statements to handle select boxes and database queries in PHP

// Assuming $conn is the database connection object

// Sanitize user input
$user_input = $_POST['user_input'];
$user_input = mysqli_real_escape_string($conn, $user_input);

// Prepare the SQL statement
$stmt = $conn->prepare("SELECT * FROM table_name WHERE column_name = ?");
$stmt->bind_param("s", $user_input);

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

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

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

Keywords

SQL injection prepared statements PDO mysqli data validation

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