PHP MySQL form selection return - php

Question

I am struggling to get this code to work, what I want from it is to show the item (that is already in the database) to be selected in the selection form.
<label>Server Ports:</label>
<select multiple class="form-control" name="select[]">
<?php
// Get Server Information
$query = "SELECT port_no FROM _servers WHERE (server_id = '$servid') ";
$result = mysql_query($query) or die ('Unable to run query:'.mysql_error());
while($row = mysql_fetch_assoc($result)){
$no = $row['port_no'];
}
$query = "SELECT id, name, port_no, unique_id FROM ports ORDER BY name ASC";
$result = mysql_query($query) or die ('Unable to run query:'.mysql_error());
while($row = mysql_fetch_assoc($result))
{
$port_no = $row['port_no'];
$port_name = $row['name'];
$p_unique = $row['unique_id'];
}
?>
<option value="<?php echo $p_unique;?>"
<?php
if ($p_unique == $no) {
$check = 'selected';
} else {
$check = '';
}
echo $check;
?>
>
<?php
echo $row['name'];
?>
(
<?php
echo $row['port_no'];
?>
)</option>
<?php
}
?>
</select>

Answer 1

Are you sure your test must be if ($p_unique == $no) {} and not if ($port_no == $no) {} ?
If yes, try to checks your variables values :
Do a var_dump() of $no :
var_dump($no);
In your while() loop, you can also check values of $p_unique and $no like that :
var_dump($p_unique.'/'.$no);
Also, here is a simplest way to test for selected :
<option value="<?php echo $p_unique;?>" <?php if ($p_unique == $no) echo 'selected="selected"'; ?>><?php echo $row['name'] ;?> (<?php echo $row['port_no'] ;?>)</option>