Difficulties with scope in Laravel - laravel

Question

I'm trying to build an application where there's a device with an expire date:
the expire date must be created with values from 2 other tables: history (last date) & model (interval)
I've create following scope in my Device model:
public function scopeExpiryDate($query, $operator) {
if ($this->histories->last() != null) {
$cal_date = $this->histories->sortBy('date')->last()->date;
$interval = $this->product->interval;
return $query->where($cal_date->addDays($interval), $operator, Carbon::now());
}
return $query;
}
Then I could use the next line:
$devices->ExpiryDate('<=')->get();
Update
like #ceejayoz told in the comments I checked the scopes section on the Laravel-site.
I edited this question.
So how do I get this scope working?

Answer 1

Assuming that $cal_date is a Carbon\Carbon instance, you can use this query:
$query->whereDate($cal_date->addDays($interval), $operator, Carbon::now());
For more information, there's a great tutorial on date filtering here

Answer 2

Ok i've found the solution. It was not found in the scopes, but in adding a attribute.
I did the following in my Device model:
public function getExpirydateAttribute() {
if ($this->histories->last() != null) {
$cal_date = $this->histories->sortBy('date')->last()->date;
$interval = $this->product->interval;
return $cal_date->addDays($interval);
}
return Carbon::now();
}
and in my view I can call something like this:
$devices->filter(function($item){ return $item->Expirydate > now()->modify('last day of this month'); })->count()
Thanks to the people who answered to my question.