recursive php category tree extended - php

Question

I have been searching all over the forum but could not locate the answer to my specific question. I hope you can help me, for it has taken me A LOT of time to figure this out as a beginning PHP programmer.
I have a page that listens to this URL : .../.../edit_cat.php?id=24
I want to have a nice category tree. I have accomplished this, but I want all categories with no children to be a link to page post.php and all parent that do have children to be a link but only to show the other categories. Some sort of dropdown menu you might call it. So no children is post.php and if has children then drop the rest of children down. I hope this makes it clear...This is whay I have so far. It works as a tree but not how I wish it to be:
<h2>This is the current category tree</h2>
<?php
category_tree(0);
function category_tree($catid){
include '../config/connect.php';
$result = $db->prepare("SELECT * FROM categories WHERE parent_id = '".$catid."'");
$result->execute();
while($row = $result->fetch(PDO::FETCH_ASSOC)):
$i = 0;
if ($i == 0){ echo '<ul class="cattree">';}
echo '<li>' . $row['cat_title'] . '';
category_tree($row['cat_id']);
echo '</li>';
$i++;
if ($i > 0){ echo '</ul>'; }
endwhile;
}
?>
My table of categories looks like this:
cat_id | cat_title | parent_id
1 some_title 0
2 some_title 1
3 title! 2
4 main_title 0
5 titellos! 4

Answer 1

Here is something I did last year, a query returns each line, with the idx, parent_idx and label of the line.
First call:
print_list(1, 0, $lines);
Function:
function print_list($parent, $level, $ar) {
$children = filter_by_parent($parent, $ar);
if (empty($children)) {
return;
}
echo '<ul>';
foreach ($children as $child) {
include PATH_PUBLIC . 'clients/simili/line.php';
print_list($child['Child_Idx'], ($level + 1), $ar);
echo '</li>';
}
echo '</ul>';
}
Second function:
function filter_by_parent($parent_id, $ar){
$retval = array();
foreach($ar as $a) {
if ($a['Parent_Idx'] == $parent_id) {
$retval[] = $a;
}
}
return $retval;
}
And the html called in the function:
<li class="no" data-id="<?php echo $child['Child_Idx']; ?>" data-parent-id="<?php echo $child['Parent_Idx']; ?>">
<i class="fa fa-plus-square-o"></i>
<i class="fa fa-minus-square-o"></i>
<span class="name">
<label><?php echo $child['Child_Name']; ?></label>
<i class="fa fa-book" title="Détails de l'Unité d'Organisation"></i>
</span>
<div class="chiffres">
<span class="inscrits"><?php echo $child['Nb_Collab']; ?></span>
<span class="etp-collab"><?php echo $child['ETP_Collab']; ?></span>
<span class="etp-postes"><?php echo $child['ETP_Postes']; ?></span>
<span class="etp-unit"><?php echo $child['ETP_Unit']; ?></span>
</div>

Answer 2

Ok, I don't know anything about PHP, but here's how you can add a "HasChildren" column to your sql query:
SELECT c.*,
CASE
WHEN EXISTS(SELECT * FROM Categories c1 WHERE c1.parent_id=c.cat_id) THEN 1
ELSE 0
END AS HasChildren
FROM Categories c
WHERE ParentID = #CatID