Build a complicated table with while/foreach - php

Question

I'm trying to build a table of results from an array. I currently have results outputting like this:
ID VALUE EXTRA
--------------------------------------
| 1 | Value 1 | Extra 1 |
|-----|---------------------|----------|
| 1 | Value 2 | Extra 2 |
|-----|---------------------|----------|
| 2 | Value 3 | Some 1 |
|-----|---------------------|----------|
| 3 | Value 4 | Some 2 |
|-----|---------------------|----------|
| 3 | Value 5 | Nothing |
--------------------------------------
Note the repeating ID value. What I'd like to do is build a loop inside my current loop that will not display duplicate IDs. Something like this:
ID VALUE EXTRA
--------------------------------------
| 1 | Value 1 | Extra 1 |
| |---------------------|----------|
| | Value 2 | Extra 2 |
|-----|---------------------|----------|
| 2 | Value 3 | Some 1 |
|-----|---------------------|----------|
| 3 | Value 4 | Some 2 |
| |---------------------|----------|
| | Value 5 | Nothing |
--------------------------------------
Here's my current code, simplified:
<?php
$i=0;
while ($i < $mynum) {
$f1=mysql_result($myresult,$i,"tableID");
$f2=mysql_result($myresult,$i,"values");
$f3=mysql_result($myresult,$i,"extra");
?>
<tr>
<td><?php echo $f1; ?></td>
<td><?php echo $f2; ?></td>
<td><?php echo $f3; ?></td>
</tr>
<?php
$i++;
}
?>
Is there a way to build this table dynamically in the way I want? Or should I rethink my strategy?

Answer 1

Assuming the IDs are sorted sequentially, store the ID in a separate variable and check to see if it has changed. If it has, print the ID; if not, print a or similar value.

Answer 2

Here a way to do it from the code you provided
<?php
$i=0;
$previousId = ''; // keeps track of the previous Id
while ($i < $mynum) {
$html = '';
$f1=mysql_result($myresult,$i,"tableID");
$f2=mysql_result($myresult,$i,"values");
$f3=mysql_result($myresult,$i,"extra");
$html .= '<tr>';
if($previousId != $f1){ // fill the cell only if the new Id is different from the previous value
$html .= '<td>'.$f1.'</td>';
} else {
$html .= '<td> </td>';
}
$previousId = $f1;
$html .= '<td>'.$f2.'</td>';
$html .= '<td>'.$f3.'</td>';
$html .= '</tr>';
$i++;
}
echo $html;
?>
But that is assuming that the $f1 are ordered.