How to calculate rank based on total marks - php

Question

I have 3 tables i want to display the 3 table data in single table based on primary key, foreign key the result came perfectly! But i need to calculate rank based on the total marks from my second table.
result screenshot:
Please anyone tell me the query to calculate rank
I used the following mysql query
if(isset($_POST['submit']))
{
$result = mysqli_query($con,"
SELECT s.student_name
, s.contact_number
, m.total
, m.rank
, p.father_name
FROM student_details s
JOIN mark m
ON s.student_id = m.student_id
JOIN parents_details p
ON p.student_id = s.student_id
WHERE s.student_name = '".$_POST['student_name']."'
");
echo "<table border='1' align='center' cellpadding='15' bgcolor='#FFFFFF'>
<tr>
<th>NAME</th>
<th>CONTACT NUMBER</th>
<th>TOTAL MARK</th>
<th>RANK</th>
<th>FATHER NAME</th>
</tr>";
while($row = mysqli_fetch_array($result))
{
echo "<tr>";
echo "<td>" . $row['student_name'] . "</td>";
echo "<td>" . $row['contact_number'] . "</td>";
echo "<td>" . $row['total'] . "</td>";
echo "<td>" . $row['rank'] . "</td>";
echo "<td>" . $row['father_name'] . "</td>";
echo "</tr>";
}
echo "</table>";
mysqli_close($con);
}?>

Answer 1

SELECT * FROM
(
SELECT #rank := #rank+1 finalrank,ZZ.* FROM
(
SELECT student_details.student_name,
student_details.contact_number, mark.total,
mark.rank, parents_details.father_name
FROM student_details
INNER JOIN mark ON student_details.student_id=mark.student_id
INNER JOIN parents_details ON parents_details.student_id=student_details.student_id ,(SELECT #rank:=0)z
ORDER BY mark.total desc
)ZZ
)ZZZ
WHERE ZZZ.student_name = '".$_POST['student_name']."'
Just try above query.
Here I had used SELECT #rank:=0 and #rank := #rank+1.