Looping <li> tag question

[smilepak]

How do I loop this? I want to group it by categories, and <li> under it by subcategories?

mysql_select_db($database_mysqlcon, $mysqlcon);
$query_rs1 = "SELECT photoID, categories, subcategories, thumbnails, largenails, comments FROM photo GROUP BY subcategories ORDER BY categories";
$rs1 = mysql_query($query_rs1, $mysqlcon) or die(mysql_error());
$row_rs1 = mysql_fetch_assoc($rs1);
$totalRows_rs1 = mysql_num_rows($rs1);
?>
<? while($row_rs1 = mysql_fetch_assoc($rs1)) { ?>
Categories: <?php echo $row_rs1['categories']; ?><br><br>
<? $categories = $row_rs1['categories']; ?>
<? if($cat !== $categories) { ?>

	<? } else { ?>
		<? while($row_rs1 = mysql_fetch_assoc($rs1)) { ?>
			Sub-Categories: <?php echo $row_rs1['subcategories']; ?><br><br>
		<? } ?>
	<? } ?>

<? } ?>

[smilepak]

How is this? Any suggestion on optimizing it?

<? $cat = 0; ?>
<? while($row_rs1 = mysql_fetch_assoc($rs1)) { ?>
<? $categories = $row_rs1['categories']; ?>

	<? if($cat !== $categories) { ?>
			Categories: <?php echo $row_rs1['categories']; ?>
			<li>Sub-Categories: <?php echo $row_rs1['subcategories']; ?></li>
			<? $cat = $row_rs1['categories']; ?>

	<? } else { ?>
			<li>Sub-Categories: <?php echo $row_rs1['subcategories']; ?></li>
			<? $cat = $row_rs1['categories']; ?>
	<? } ?>

<? } ?>

[PallaviDalvi]

u need not have to enclose each statement in <?... ?>. if i'm not wrong... doing so increases the load on the server and lowers efficiency. so ur code cud be re-written as ....

<?
$cat = 0;  

while($row_rs1 = mysql_fetch_assoc($rs1)) 
{  

	$categories = $row_rs1['categories'];  

if($cat !== $categories) 
{  
	echo "Categories: " . $row_rs1['categories'];  
	echo "<li>Sub-Categories: ". $row_rs1['subcategories']. "</li>"; 
	$cat = $row_rs1['categories'];  

 }
 else 
 {  
	 echo "<li>Sub-Categories: ".$row_rs1['subcategories'] . "</li>"; 
	 $cat = $row_rs1['categories'];  
 }  
 } 
 ?>

!== operator is used to make comparisions based on value and datatype. am not very sure if u wud want to do any such comparisons here.

the database needs to be optimized. ideally i wud be having a table for the main categories and one for sub-categories(having a field 'parent_category' to identify the main-category to which it belongs.)

[smilepak]

Cool thanks for the input. I didn't know you could do without all the <? ?>, let me update that.