Average of horizontals data mysql php - php

Question

I hope you are doing well. I am working in a school management project , i want to get the average of 5 test(devoir) of each subject(Matiere) like-
i tried to use AVG() inside while loop of getting horizontale devoir data, i got no result ,any suggestions ??
$query5 = "select * from devoir where CIN_ELEVE = '$cinE' and ID_ELV_AN_CLS = $select2 GROUP BY MODULE_DEVOIR";
$result5 = mysqli_query($con,$query5);
if(mysqli_num_rows($result5)>0)
{
echo"<table class='table table-bordered table-striped table-hover table-info'><tr>
<th>MATIERE</th>
<th>devoir1</th>
<th>devoir2</th>
<th>devoir3</th>
<th>devoir4</th>
<th>devoir5</th>
<th>AVG</th>
</tr>
";
while($rows = mysqli_fetch_assoc($result5))
{
$moduleD = $rows['MODULE_DEVOIR'];
$queryDEV = "select * from devoir inner join eleve on devoir.CIN_ELEVE = eleve.CIN_ELEVE where eleve.CIN_ELEVE = '$cinE' and MODULE_DEVOIR = '$moduleD' order by MODULE_DEVOIR";
$resultDEV = mysqli_query($con,$queryDEV);
/*to print subject name*/
echo"<tr><td>$moduleD</td>";
while($rows = mysqli_fetch_assoc($resultDEV))/*loop2*/
{
$noteDEV = $rows['NOTE_DEVOIR'];
/*to print subject mark(note)*/
echo"<td>$noteDEV</td>";
/*i add the query of average inside the loop to be with touch by all row data mark*/
$queryAVG="select avg($noteDEV) as average_devoir from devoir where MODULE_DEVOIR = '$moduleD' group by MODULE_DEVOIR ";
}
$resultAVG = mysqli_query($con,$queryAVG);
if($rows = mysqli_fetch_assoc($resultAVG))
{
if($rows = mysqli_fetch_assoc($resultAVG))
{
$avg = $rows['average_devoir'];
echo"<td>$avh</td>";
}
}
echo"</tr>";
}
echo"</table>";
}

Answer 1

If you are not required to use SQL to calculate the average, then doing this seems a better option.
while($rows = mysqli_fetch_assoc($result5))
{
$moduleD = $rows['MODULE_DEVOIR'];
$queryDEV = "SELECT * FROM devoir INNER JOIN eleve " .
"ON devoir.CIN_ELEVE = eleve.CIN_ELEVE " .
"WHERE eleve.CIN_ELEVE = '$cinE' " .
"AND MODULE_DEVOIR = '$moduleD' " .
"ORDER BY MODULE_DEVOIR";
$resultDEV = mysqli_query($con,$queryDEV);
/*to print subject name*/
echo"<tr><td>$moduleD</td>";
// We will use this variable to store the sum
$sum = 0;
// And this is a counter to store the number of results
$count = 0;
while($rows = mysqli_fetch_assoc($resultDEV))/*loop2*/
{
$noteDEV = $rows['NOTE_DEVOIR'];
/*to print subject mark(note)*/
echo"<td>$noteDEV</td>";
// Update the sum
$sum += $noteDEV;
// Update the counter
$count ++;
}
// Calculate and display the average
$avg = $sum / $count;
echo "<td>$avh</td>" . "</tr>";
}
If you know that the number of results is always constant, and equals 5, you can get rid of the $count variable and divide by 5 directly.
You may also wish to format the output to fit your needs.