Php 对SQL字段求和以获得总结果

我试图对SQL数据库中的许多字段求和。 这些字段称为week1到Week13，因为它们存储每周的结果。 我有这个在目前，但它不是输出任何东西，任何帮助将不胜感激。干杯

<?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;

            }
        ?>

就足够了
SUM（）
是一个聚合函数，用于添加行。要添加列，只需使用
+
，但请注意，如果任何列为空，则可能无法获得预期的结果

SELECT IFNULL(week1, 0) + IFNULL(week2, 0) + IFNULL(week3, 0) AS sumweeks //etc

这应该能奏效。
（假设：每个用户有多行。如果每个用户只有一行，则可以省略sum函数和group by子句）
SQL不是这里唯一的问题-mysql\u查询不返回值。您必须使用mysql\u fetch\u array（）来获取它。$result=mysql\u fetch\u array（$query）；回声$结果；我现在添加了抓取和打印-除了现在它打印单词数组..事实上，
GROUP BY
两种方式都可以省略，因为您只为单个用户检索行。什么会导致它无法打印出来？因为mysql\u查询输出查询结果，您应该使用
mysql\u-fetch\u-assoc
或
mysql\u-fetch\u-row
等获取它。$result=mysql\u-fetch\u-assoc（$query）；回声$结果；我已经添加了它，它会打印出“数组”
SELECT IFNULL(week1, 0) + IFNULL(week2, 0) + IFNULL(week3, 0) AS sumweeks //etc

 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