PHP find parents of leaf and build tree - php

Question

I have a quite simple task but I lost somewhere. I have categories table with common structure: id, id_parent, some other fields less important. I need to build multidimensional array from parents to children nodes like this:
array(
'id' => 1,
'id_parent' => 0,
'name' => 'Main',
'children' => array(
'id' => 2,
'id_parent' => 1,
'name' => 'Main-sub',
'children' => array(
'id' => 3,
'id_parent' => 2,
'name' => 'Main-sub-sub'
)
)
)
I have given id of category (e.g. id = 3). I need to find very first parent of this category and then build tree traversing down. I'm tried simplest method using if statement recursively, but order of array I got is reversed. This is how it looks like at this moment:
public function getCategoryById($id)
{
$branch = array();
$data = $this -> db -> query("SELECT categories.* FROM categories WHERE categories.visible = 1 AND categories.id = {$id} ORDER BY categories.position -- LIMIT 1");
if(is_array($data))
{
foreach($data as $item)
{
if($item['id_parent'] != 0)
{
// do it again recursively
$parent = $this -> getCategoryById($item['id_parent']);
$branch['parents'] = $parent;
// lost here
}
// lost here also
$branch[] = $item;
}
}
return $branch;
}
I have searched threads and found few questions similar to mine, but solutions doesn't work in my case.
Any help would be appreciated.

Answer 1

You might be better off with a function that finds all of the children for a category given an ID and returns the structure you are looking for.
public function getChildrenForCategory($id)
{
$children = array();
$data = $this -> db -> query("SELECT categories.* FROM categories WHERE categories.visible = 1 AND categories.id_parent = {$id} ORDER BY categories.position");
if(is_array($data))
{
foreach($data as $item)
{
// do it again recursively
$subChildren = $this -> getChildrenForCategory($item['id']);
$item['children'] = $subChildren;
array_push($children, $item);
}
}
return $children;
}