Create a nested list - php

Question

How would I create a nested list, I currently have this
public function getNav($cat,$subcat){
//gets all sub categories for a specific category
if(!$this->checkValue($cat)) return false; //checks data
$query = false;
if($cat=='NULL'){
$sql = "SELECT itemID, title, parent, url, description, image
FROM p_cat
WHERE deleted = 0
AND parent is NULL
ORDER BY position;";
$query = $this->db->query($sql) or die($this->db->error);
}else{
//die($cat);
$sql = "SET #parent = (SELECT c.itemID FROM p_cat c WHERE url = '".$this->sql($cat)."' AND deleted = 0);
SELECT c1.itemID, c1.title, c1.parent, c1.url, c1.description, c1.image, (SELECT c2.url FROM p_cat c2 WHERE c2.itemID = c1.parent LIMIT 1) as parentUrl
FROM p_cat c1
WHERE c1.deleted = 0
AND c1.parent = #parent
ORDER BY c1.position;";
$query = $this->db->multi_query($sql) or die($this->db->error);
$this->db->store_result(); $this->db->next_result();
$query = $this->db->store_result();
}
return $query;
}
public function getNav($cat=false, $subcat=false){
//gets a list of all categories form this level, if $cat is false it returns top level nav
if($cat==false || strtolower($cat)=='all-products') $cat='NULL';
$ds = $this->data->getNav($cat, $subcat);
$nav = $ds ? $ds : false;
$html = '';
//create html
if($nav){
$html = '<ul>';
//var_dump($nav->fetch_assoc());
while($row = $nav->fetch_assoc()){
$url = isset($row['parentUrl']) ? $row['parentUrl'].'/'.$row['url'] : $row['url'];
$current = $subcat==$row['url'] ? ' class="current"' : '';
$html .= '<li'.$current.'>'.$row['title'].'</li>';
}
$html .='</ul>';
}
return $html;
}
The sql returns parents and children, for each parent I need the child to nest in a list.

Answer 1

It's been a while since I've done any PHP but wondering if this will work. Inside your while loop, could you just recurse and add the output of getNav($cat = $row['url']) again in a new <li>, kind of like:
while($row = $nav->fetch_assoc()){
$url = isset($row['parentUrl']) ? $row['parentUrl'].'/'.$row['url'] : $row['url'];
$current = $subcat==$row['url'] ? ' class="current"' : '';
$html .= '<li'.$current.'>'.$row['title'].'';
/* Add subNav HTML */
$html .= $this->getNav($row['url']);
$html .= '</li>';
}
It seems that "getNav" refers to both the function to get the SQL as well as the function that renders the nav HTML - maybe change the HTML getNav function name to getNavHtml just for clarity.
Also seems like the $subcat argument may be able to be removed from the SQL getNav function since it is never used.