grouping class names together in my CMS php - php

Question

I am done with a CMS school system which i created from scratch for practice in php. My question is for example I have Accounting 101, Computer Science 101, however there must multiple times for Accounting 101. For example: Ticket 1035, 1036 are both Accounting 101 and they should appear in the same table, but in my code it shows them in different classes. Here is my code.
if(isset($_GET['id']))
{
$category = $_GET['id'];
$sql = "SELECT * FROM classes WHERE category_id = " . $category;
$query2 = mysql_query($sql) or die(mysql_error());
while($row = mysql_fetch_object($query2))
{
?>
<center><h3><?php echo $row->class_name . '-' . $row->units; ?> </h3></center>
<table border ="0" wdith="100%">
<tr>
<td>
<strong>Description: </strong>
<?php echo $row->class_description; ?>
</tr>
</td>
</table>
<br/>
<table border="1" width="44%">
<tr>
<td width="60"><b>Ticket</b> </td>
<td width="123"><b>Days</b></td>
<td width="120"><b>Hours</b></td>
<td width="64"><b>Room</b></td>
<td><b>Instructor</b></td>
</tr>
<tr>
<td width="60"> <?php echo $row->ticket; ?> </td>
<td width="123"><?php echo $row->days; ?></td>
<td width="120"><?php echo $row->start_hours . $row->time_format . '-' . $row->end_hours . $row->time_format2 ; ?> </td>
<td width="64"> <?php echo $row->room_number; ?></td>
<td><?php echo $row->instructor_name; ?></td>
</tr>
}//end while
}//end if
Its showing Accounting 101 with different tickets in different tables, but it should be all in 1 table. Thanks.

Answer 1

You need a double loop if you're trying to get records inside of records. For example:
while ($row1 = mysql_fetch_object($query1))
{
echo $row1->ParentName;
$query2 = 'select * from `mytable` where `myForeignKey` = ' . $row1->ParentId;
while ($row2 = mysql_fetch_object($query2))
{
echo $row2->ChildName;
}
}
You could also do a left join. Let me know if you need a sample of that.
Edit:
The left join would be done like this:
$sql = "select * from `classes` as a where category_id = '{$category}' left join `tickets` as b on a.id = b.class_id"
Ref. http://www.w3schools.com/sql/sql_join_left.asp