Vergleich von zwei Tabellen in Laravel mit dem Modell
$paidFeesIds = Fee::whereHas('paidFees', function($q) {
$q->where('payment_status', 1);
})->pluck('id')->toArray();
$notPaidFeesIds = Fee::whereNotIn('id', $paidFeesIds)->pluck('id')->toArray();
Anxious Anteater