php mysql结果添加html标签

Here is some php mysql query code. I want make some query with pagination. each page have 10 results.

$sql = mysql_query("SELECT * FROM article WHERE uid='132828' ORDER BY date LIMIT ".$number.",10 ");
$num = 1;
while($row = mysql_fetch_array($sql)){
   if($num ==1){
       echo '<ul class="left">';
   }
   if($num ==5){
       echo '<ul class="right">';
   }
   //what about these code here? 
   if($num%5==0){
       echo '</ul>';
   }
}

And I want out put the html like:

<ul class="left">
  <li> 1st result </li>
  <li> 3rd result </li>
  <li> 5th result </li>
  <li> 7th result </li>
  <li> 9th result </li>
</ul>
<ul class="right">
  <li> 2nd result </li>
  <li> 4rd result </li>
  <li> 6th result </li>
  <li> 8th result </li>
  <li> 10th result </li>
</ul>

So, how to add html tags in this situation? Thanks.

you are not incrementing $num try this

$num = 1;
while($row = mysql_fetch_array($sql)){
   if($num ==1){
       echo '<ul class="left">';
   }
   if($num ==5){
       echo '<ul class="right">';
   }
   //what about these code here? 
   if($num%5==0){
       echo '</ul>';
   }
   $num++ ;

}

Try this code:-

$num = 1;
$ul_first= '<ul class="left">';
$ul_second= '<ul class="right">';
while($row = mysql_fetch_array($sql)){
   if(($num%2)==1){
       $ul_first.= '<li>'.$row['result'].'</li>';
   }
   if(($num%2)==0){
       $ul_second.='<li>'.$row['result'].'</li>';
   }

   if(($num%10)==0){
       $ul_first.= '</ul>';
       $ul_second.= '</ul>';
   }
   $num++ ;

}
echo $ul_first;
echo $ul_second;