Building 3 level tree from database

[warozzo]

If in MySQL I have data like this:

+------------+------------+----------+
|    date    |     url    | topic    |
+------------+------------+----------+
| 2011-07-00 | ./url?go=1 | news     |
| 2011-07-00 | ./url?go=2 | sports   |
| 2011-07-00 | ./url?go=3 | politics |
| 2011-06-00 | ./url?go=4 | news     |
| 2011-06-00 | ./url?go=5 | sports   |
| 2011-06-00 | ./url?go=6 | politics |
| 2011-05-00 | ./url?go=7 | news     |
| 2011-05-00 | ./url?go=8 | sports   |
| 2010-12-00 | ./url?go=9 | politics |
| 2010-12-00 | ./url?go=7 | news     |
| 2010-12-00 | ./url?go=8 | sports   |
| 2010-12-00 | ./url?go=9 | politics |
+------------+------------+----------+

and if I want to generate list like this below:

<ul>
  <li>2011
    <ul>
      <li>07
        <ul>
          <li><a href="{url}">{topic}</a></li>
          <li><a href="{url}">{topic}</a></li>
          <li><a href="{url}">{topic}</a></li>
        </ul>
      </li>
      <li>06
        <ul>
          <li><a href="{url}">{topic}</a></li>
          <li><a href="{url}">{topic}</a></li>
          <li><a href="{url}">{topic}</a></li>
        </ul>
      </li>
      <li>05
        <ul>
          <li><a href="{url}">{topic}</a></li>
          <li><a href="{url}">{topic}</a></li>
          <li><a href="{url}">{topic}</a></li>
        </ul>
      </li>
    </ul>
  </li>
  <li>2010
    <ul>
      <li>07
        <ul>
          <li><a href="{url}">{topic}</a></li>
          <li><a href="{url}">{topic}</a></li>
          <li><a href="{url}">{topic}</a></li>
        </ul>
      </li>
    </ul>
  </li>
</ul>

I know how to split the date, but I don't know how to generate the list.
Would someone help me on this? Thanks.

[leatherback]

You keep track of the last date during your loop. As you reach a new date, you spit out the separater:

$lastdate = '';
while($row ...)
  {
  if($row['date'] <> $lastdate && $lastdate <>'')
    {
    echo "</ul>
      </li>
      <li>
        <ul>";
    }
  // spit out whatever you need
  echo 'lalala';

  // set the lastdate var
  $lastdate = $row['date'];
  }

[warozzo]

Thanks for your answer, I'll try it immediately.