while loop in mysql inner join - php

Question

My code join 4 table using INNER JOIN. I can't customize loop while using inner join. How to control while clause so unwanted loop wouldn't happen.
My code output (student and school name is looping in every subject field)
I want to display like this where student and school loops at once.
MY PHP Code
<table id="customers">
<?php
$query=$con->prepare("SELECT subjectcomb.subjectid, subjectcomb.schoolid, student.student, school.school, subject.name
FROM ((( subjectcomb
INNER JOIN school ON subjectcomb.schoolid=school.id)
INNER JOIN student ON subjectcomb.schoolid=student.schoolID)
INNER JOIN subject ON subjectcomb.subjectid=subject.id)");
$query->execute();
while ($row = $query->fetch(PDO::FETCH_ASSOC)){?>
<tr>
<td>
<?php echo $row['school']."->".$row['student']?>
</td>
</tr>
<tr>
<td>
<?php echo $row['name']?>
<input type="text" name="mark"></input>
</td>
</tr>
<?php } ?>
</table>

Answer 1

Try adding an ORDER BY to your query:
$query=$con->prepare("SELECT subjectcomb.subjectid, subjectcomb.schoolid, student.student, school.school, subject.name
FROM ((( subjectcomb
INNER JOIN school ON subjectcomb.schoolid=school.id)
INNER JOIN student ON subjectcomb.schoolid=student.schoolID)
INNER JOIN subject ON subjectcomb.subjectid=subject.id)
ORDER BY school.school, student.student");
then in the while loop use this check:
<?php
$last_student = ""
while ($row = $query->fetch(PDO::FETCH_ASSOC)){
if ($last_student != $row['student']) {
?>
<tr>
<td>
<?php echo $row['school']."->".$row['student']?>
</td>
</tr>
<?php } ?>
<tr>
<td>
<?php echo $row['name']?>
<input type="text" name="mark"></input>
</td>
</tr>
<?php $last_student = $row['student'] } ?>

Answer 2

I think what Phil meant was something like the following. You keep track of the previous school and student. If the current school and student are the same as the previous, you skip printing the school/student row, but if they not the same, you print them and also update the previous school's and previous student's values.
$prev_school = '';
$prev_student = '';
while ($row = $query->fetch(PDO::FETCH_ASSOC)) {
if ($row['school'] != $prev_school && $row['student'] != $prev_student) { ?>
<tr>
<td>
<?php echo $row['school']."->".$row['student'] ?>
</td>
</tr>
<?php
$prev_school = $row['school'];
$prev_student = $row['student'];
}
?>
<tr>
<td>
<?php echo $row['name']?>
<input type="text" name="mark"></input>
</td>
</tr>
<?php
}