Printing categories recursivly

[Petal]

Hi!
I am developing a page where I have categories at many levels. I would like to always show the categories on level 1. When one category at level 1 is selected, I would like to show the categories that belong to this category and at the same time show all categories at level 1. I would like to use undetermined number of levels. And it would be different numbers of levels at every category.

I am using a mySQL databse. I have tried to make this script, but I cant make it work.

I am using a tabel with:
category_id,category_dad and category_name
category_dad is the category_id to the category that this category belongs to.

Categories at level 1 has a category_dad=0.

The code i have tried:

<?php
function write_category($category_id,$category_dad){
$sql =&quot;select category_name, category_id,category_dad from category&quot;;
$sql=$sql.&quot; where category_dad=$category_dad&quot;;
$sql=$sql.&quot; order by category_name&quot;;
$resultat = mysql_query($sql);
$resultat2 = mysql_query($sql);
$s=0;
$r=0;
while($rad = mysql_fetch_array($resultat)){
if($category_id==$category_dad){
$s=1;
$r=1;
}
if($s==0){
if(write_category($category_id,$rad[&quot;category_id&quot;])){
$r=1;
$s=1;
}
}
if($s==0){
if($category_id==$rad[&quot;category_id&quot;]){
$s=1;
$r=1;
}
}
}

if($s==1){
while($rad = mysql_fetch_array($resultat2)){
echo &quot;<tr><td ><a class='menu' target='_self' href='meny.php?category_id=&quot;.$rad[&quot;category_id&quot;].&quot;'>&quot;.$rad[&quot;category_name&quot;].&quot;</a></td></tr>&quot;;

}
}

if($r==1){
return true;
}
}
if(!isset($category_id))$category_id=0;
write_category($category_id,0);
?>
This code almost work. But i would like to print it out like this:
Airplanes
Cars
Opel
BMW
Mercedes
Motobikes

Not like this:
Opel
BMW
Mercedes
Airplanes
Cars
Motobikes

When Opel,BMW and Mercedes belong to the category Cars..

Can anybody please help me?

Jørn Arild Andenæs
jaa@jaa.no

 

[sleipnir214]

You're not real big on indenting code, are you?

You're not going to be able to do a recursive output of a category and all it's immediate children in one SQL statement.

I recommend that you loop through the top-level categories, and when you get to the category whose children you want to see, perform an interior loop to output those children.

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TANSTAAFL!