How can special characters in PHP code affect SQL syntax errors when inserting data into a database?

Special characters in PHP code can affect SQL syntax errors when inserting data into a database because they can interfere with the SQL query structure. To prevent this issue, it is important to properly escape special characters before inserting them into the database. This can be done using functions like mysqli_real_escape_string() or prepared statements to ensure that the data being inserted is safe and does not cause any SQL syntax errors.

// Example of using mysqli_real_escape_string to escape special characters before inserting data into a database

// Assuming $conn is the mysqli connection object

$name = mysqli_real_escape_string($conn, $name);
$email = mysqli_real_escape_string($conn, $email);
$age = mysqli_real_escape_string($conn, $age);

$sql = "INSERT INTO users (name, email, age) VALUES ('$name', '$email', '$age')";

if(mysqli_query($conn, $sql)){
    echo "Data inserted successfully";
} else{
    echo "Error: " . mysqli_error($conn);
}