Simple PHP function questionfrom noob!

programming
1

How do i write this code outside of a function, i have a tutorial but it shows me how to convert script into a function but this example below never did, it was just wrote straight into a function.

function get_subject_by_id($subject_id) {
    global $connection;
    $query = "SELECT * ";
    $query .= "FROM subjects ";
    $query .= "WHERE id=" . $subject_id ." ";
    $query .= "LIMIT 1";
    $result_set = mysql_query($query);
    // REMEMBER:
    // if no rows are returned, fetch_array will return false
    if ($subject1 = mysql_fetch_array($result_set)) {
        return $subject1;
    } else {
        return NULL;
    }
}