CODEWITHSUNDEEP
phpmysqlsum
user2227817
user2227817

Reputation: 3

Sum columns using MySQL/PHP

My question is that why there are blank values for HW1/HW2/HW3 columns when I ran the code in the browser?.
Studentid and Sum columns displayed the code correctly. Any ideal how to fix this?

<?php

$result = mysqli_query($con,"SELECT studentid,SUM(hw1+hw2+hw3) 
FROM grade
GROUP BY studentid");

echo "<table border='1'>
<tr>
<th>StudentID</th>
<th>HW1</th>
<th>HW2</th>
<th>HW3</th>
<th>SUM</th>

</tr>";

while($row = mysqli_fetch_array($result))
 {
 echo "<tr>";
 echo "<td>" . $row['studentid'] . "</td>";
 echo "<td>" . $row['hw1'] . "</td>";
 echo "<td>" . $row['hw2'] . "</td>";
 echo "<td>" . $row['hw3'] . "</td>";
 echo "<td>" . $row['SUM(hw1+hw2+hw3)'] . "</td>";

 ;}

 echo "</table>";

 mysqli_close($con);
?>

Upvotes: 0

Views: 232

Answers (3)

daksh21ubuntu
daksh21ubuntu

Reputation: 276

just change your query to this

"SELECT studentid,hw1, hw2, hw3, SUM(hw1+hw2+hw3) as hw
FROM grade
GROUP BY studentid"

Upvotes: 1

Tim
Tim

Reputation: 953

Because you did not select the columns, try:

$result = mysqli_query($con, 'SELECT `studentid`, `hw1`, `hw2`, `hw3`, SUM(`hw1`+`hw2`+`hw3`) as `sum` FROM `grade` GROUP BY `studentid`');

while($row = mysqli_fetch_array($result)) {
    echo "<tr>";
    echo "<td>" . $row['studentid'] . "</td>";
    echo "<td>" . $row['hw1'] . "</td>";
    echo "<td>" . $row['hw2'] . "</td>";
    echo "<td>" . $row['hw3'] . "</td>";
    echo "<td>" . $row['sum'] . "</td>";
}

Upvotes: 0

Matt
Matt

Reputation: 1131

I'm not sure, since your question is poorly written. But I think you just need to do this to get the values:

SELECT studentid,hw1,hw2,hw3,SUM(hw1+hw2+hw3)

Upvotes: 0

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