Question

I am trying to Sum a number of fields within a SQL Database.
The fields are called week1 to week 13 as they store results for each week.
I have this at the moment however it is not outputting anything, any help would be appreciated. Cheers

<?php
            if ($resultsRows == 0){
            echo '<p> No results have been listed for you yet. </p>';
            }
            if ($resultsRows > 0){              
            $qrytotalresult = "SELECT SUM(week1 + week2 + week3 + week4 + week5 + week6 + week7 + week8 + week9 + week10 + week11 + week12 + week13) FROM results WHERE username = '$username'";
            $TotalResult = mysql_query($qrytotalresult);
            return $TotalResult;

            }
        ?>

Answer 1

 SELECT SUM(week1) + SUM(week2) + SUM(week3) + SUM(week4) + SUM(week5) +  
        SUM(week6) + SUM(week7) + SUM(week8) + SUM(week9) + SUM(week10) +  
        SUM(week11) + SUM(week12) + SUM(week13) 
 FROM results 
 WHERE username = '$username' 
 group by username

This should do the trick.
(Assumption: There are multiple rows for each user. If each user has only one row than sum function and group by clause can be omitted)