php - 我想对我的 GPA 点列求和然后我想用行划分完整的总和

Question

我想对我的 GPA 点列求和，然后我想根据我的列 (Class=Secession=roll) 从数据库中用行划分完整总和。然后我会回应完整的等级。请高手兄帮帮我。我还是学习者。谢谢大家

this is my database

<?php  
        include 'connect.php';
        $class_n =$_POST['class_n'];
        $class_s =$_POST['class_s'];
        $r =$_POST['roll'];

        $sql="select SUM(point) AS gpa from full_result where class_n='$class_n' AND class_s='$class_s' AND roll='$r'";
        $data = mysql_query($sql);
        $c = $gpa / 5;
        echo $c;
?>

Answer 1

您需要从结果集中提取出 gpa 别名。在最初的问题中，您使用的是从未分配的变量 $gpa。

$sql="select SUM(point) AS gpa from full_result where class_n='$class_n' AND class_s='$class_s' AND roll='$r'";
$data = mysql_query($sql);

$row = mysql_fetch_assoc($data);
$gpa = $row["gpa"];
$c = $gpa / 5;
echo $c;