How to display subcategory related to category using laravel - laravel

Question

I am trying to display subcategory to related category in this menu firsrt category has been displayed but i have to display subcatory to relate category ?
Database
category table
front page
controller
public function index(){
$category=DB::table('category')->where('p_id',0)->get();
return view('front_end/index',compact('category'));
}
html view
<div class="nav-panel__nav-links nav-links">
<ul class="nav-links__list">
#foreach($category as $firstmenu)
<li class="nav-links__item nav-links__item--has-submenu ">
<a id="cate" class="nav-links__item-link" href="
{{$firstmenu->cate_name}}">
<div class="nav-links__item-body">
{{$firstmenu->cate_name}}
<svg class="nav-links__item-arrow" width="9px" height="6px">
<use xlink:href="public/assets/images/sprite.svg#arrow-rounded-down-9x6"></use>
</svg>
</div>
</a>
<div class="nav-links__submenu nav-links__submenu--type--megamenu nav-links__submenu--
size--nl">
<!-- .megamenu -->
<div class="megamenu ">
<div class="megamenu__body">
<div class="row">
<div class="col-6">
<ul class="megamenu__links megamenu__links--level--0">
<li class="megamenu__item megamenu__item--with-submenu ">
/sub category /
T-shirts
<ul class="megamenu__links megamenu__links--level--1">
/sub category /
<li class="megamenu__item">short paint
</li>
</ul>
</li>
</ul>
</div>
</div>
</div>
</div>
<!-- .megamenu / end -->
</div>
</li>
#endforeach
</ul>
</div>

Answer 1

so at first you need to fetch this subcategory somehow. You can use eloquent relationship if defined or simple join like so:
DB query:
$category = DB::table('category')
->join('subcategory', 'subcategory.category_id', '=','category.id')
->where('p_id',0)
->get();
Eloquent(if category have more than one subcategory):
Category Model:
public function subcategory()
{
return $this->hasMany(SubCategory::class, 'category_id', 'id');
}
Controller
$category = Category::with('subcategory')->get();
And then just get the name or some other value of subcategory in view (important - if there could be more subcategories related to your category than just one you have to use loop to itereate through all subcategories):
{{$category->subcategory->name}}
Or
#foreach($category->subcategory as $sub_cat)
{{$sub_cat->name}}
#endforeach
For more informations you should check Laravel documentation:
https://laravel.com/docs/6.x/eloquent-relationships

Answer 2

As you have posted the table structure
Your relationship will be like
public function subCategories(){
return $this->hasMany(SELF::class, 'p_id', 'id');
}
public function parentCategories(){
return $this->hasMany(SELF::class, 'p_id', 'id');
}
public scopeParent($query){
return $query->whereNull('p_id');
}
public scopeChild($query){
return $query->whereNotNull('p_id');
}
And you should be able to get the categories like
$categories = Category::parent()->get();
and then something like this
foreach($categories->with('subCategories')->get() as $category) {
foreach($category->subCategories as $subCategory) {
}
}