Retrieve Models with invalid Category Subcategory relations - laravel

Question

I have three Models Record, Category and Subcategory. The Record table stores category_id and subcategory_id as foreign keys. There is a pivot table "category_subcategory".
I would like to retrieve all Records that have an "invalid Category Subcategory relation" in an elegant and performant way via a custom function in the Model.
What do I mean by "invalid Category Subcategory relations":
a) Record has as Categroy and Subcategory. But the Subcategory doesn't belong to the Category (No entry in pivot table)
b) Record has a Category but no Subcategory (subcategory_id = NULL). Because the Category itself has Subcategories, the subcategory_id of the Record should be NULL
c) Record has a Category and a Subcategory, but the Cateory itself has no Subcategories, therefore the Record should have the subcategory_id = NULL
With this custom function in the Model I would like to be able to do sth like this in a Controller:
Records::withInvalidCategorySubcategoryRelation()->get(); //or similar
rather than going through endless foreach loops in the Controller like
$records = Record::all();
foreach($records as record){ ...
Any suggestions are much appreciated!
Here are my Model Classes:
class Record extends Model
{
public function category()
{
return $this->belongsTo(Category::class);
}
public function subcategory()
{
return $this->belongsTo(Subcategory::class);
}
}
class Category extends Model
{
public function subcategories()
{
return $this->belongsToMany(Subcategory::class);
}
}
class Subcategory extends Model
{
public function categories()
{
return $this->belongsToMany(Category::class);
}
}

Answer 1

Laravel offers whereNotExists that can be helpful here.
Add the following function to Record model:
// Adjust the func name as per your test ;)
public function scopeInvalidRecords($query)
{
return $query->whereNotExists(function($q) {
$q->select(\DB::raw(1))
->from('category_subcategory')
->whereRaw('
category_subcategory.category_id = records.category_id
AND
category_subcategory.subcategory_id = records.subcategory_id
');
});
}
In Controller:
Record::invalidRecords()->get();
// It'll give you all the invalid records(invalid as per your definition)
Hope it is helpful!

Answer 2

Thanks to #Zeshan Khattak I was able to get what I needed. Now I get the "invalid" Records where a) b) c) is met
public function scopeInvalidRecords($query)
{
return $query->whereExists(function($q) {
$q->select(\DB::raw(1))
->from('category_subcategory')
->whereRaw('
category_subcategory.category_id = records.category_id
');
})->whereNotExists(function($q) {
$q->select(\DB::raw(1))
->from('category_subcategory')
->whereRaw('
category_subcategory.category_id = records.category_id
AND
category_subcategory.subcategory_id = records.subcategory_id
');
})->orWhereNotExists(function($q) {
$q->select(\DB::raw(1))
->from('category_subcategory')
->whereRaw('
category_subcategory.category_id = records.category_id
');
})->whereNotNull('subcategory_id');
}