All categories are not showing in header from db

I'm trying to get all main categories in the header of site but only one category is showing, here is link of pic of admin panel where records are coming from db:

https://imageshack.com/i/plRp0Inbp

and here is link of pic of index page where only 1 category is showing:

https://imageshack.com/i/plIIRDDBpcan anyone provide the solution for this?

Here is ProductsController:

  public function products($url = null)
 {

  $categories = Category::with('products')->where(['parent_id'=>0])->get();
  $categoryDetails = Category::where(['url' => $url])->first();

  if($categoryDetails->parent_id==0)
  {
    //if url is main category url
    $subCategories = Category::where(['parent_id'=>$categoryDetails])->get();
    $cat_ids = "";
    foreach ($subCategories as $subCat) {
       $cat_ids .= $subCat->id.",";
   }
     $productsAll = Product::whereIn('category_id',array($cat_ids))->get();
 }
 else
 {
    //if url is sub category url
     $productsAll = Product::where(['category_id' => $categoryDetails->id])
                      ->get();
 }

 return view('products.listing')
          ->with(compact('categories','categoryDetails','productsAll'));
 }

and on the listing.blade.php I write this to relate it with categories:

  {{ $categoryDetails->name }}

Code of Controller: (default Controller.php)

     <?php

  namespace App\Http\Controllers;

 use Illuminate\Foundation\Bus\DispatchesJobs;
 use Illuminate\Routing\Controller as BaseController;
 use Illuminate\Foundation\Validation\ValidatesRequests;
 use Illuminate\Foundation\Auth\Access\AuthorizesRequests;
 use App\Category;

class Controller extends BaseController
{
 use AuthorizesRequests, DispatchesJobs, ValidatesRequests;

 public static function mainCategories(){
 $mainCategories = Category::where(['parent_id' => 0])->get();
 //$mainCategories = json_decode(json_encode($mainCategories));
  /*echo "<pre>"; print_r($mainCategories); die;*/
 return $mainCategories;
   }
  }

The code I write in the header view:

header.blade.php

  <?php use App\Http\Controllers\Controller;
  $mainCategories =  Controller::mainCategories();
  ?>

  <!--some html-->

  @foreach($mainCategories as $cat)
      <div class="dropdown-content">
           <a href="{{ asset('products/'.$cat->url) }}" style="margin-bottom: -10px;">{{ $cat- 
    >name }}</a>
      </div>
  @endforeach