Treelist data to navigation

Question

I'm trying to do a navigation. I have treelist for products.

Products
-product A
 --product A.1
 --product A.2
  ---product A.2.1
-product B
 --product B.1

How can i show in my navigation only the parent. For example,

Products
-product A
-product B

I use cakephp 3.0. I make this treelist based on the tutorial blog.Can anyone help me?

This is my controller.

   public function index()
    {
        $products = $this->Products->find()
            ->order(['lft' => 'ASC']);
        $this->set(compact('products'));
        $this->set('_serialize', ['products']);
    }

Answer 1

let's suppose you don't have a root node in your tree.

I understand you want to retrieve all and just the nodes that are at the firt level. In this case you are looking for the nodes who have a NULL parent_id

$products = $this->Products->find('treeList')
    ->where(['parent_id IS NULL']);

instead if you have a root node which id is i.e. 1

$root_id = 1;
$products = $this->Products->find('treeList')
    ->where(['parent_id' => $root_id ]);