php - Laravel validation with condition on a specific column

one text

Solution:

public function store(Request $request) {
    $this->validate($request, [ 'start_date' => ['unique:reservations,start_date,NULL,NULL,pitch_id,'.$request->input('pitch_id')]
    ]); 
    $events = Reservation::create($request->all());
    return redirect('Reservations')->with('success', 'réservation crée avec succès');
}

https://laravel.com/docs/8.x/validation#rule-unique