I’m a bit new to a project Laravel and i’m currently block on an error since hours.

I’m trying to make a select multiple, it’s working when the select is unique but when i try to have the possibility to select multiple option, it doesn’t work.

Here the view :

            <label for="operation_id" class="text-gray-700 inline-block">Opération</label>
        <select class="focus:outline-none outline-none w-full px-3 py-2 border rounded {{ $errors->has('operation_id') ? 'border-red-400' : '' }} select-checkbox" name="operation_id[]" id="operation_id" multiple>
            @foreach ($operations as $operation)
                @if (old('operation_id', $offer->operation_id ?? '') == $operation->id)
                    <option value="{{ $operation->id }}" selected {{ in_array($operation->id,  old('operation_id') ?: []) }}>{{ $operation->translation->name }}</option>
                @else
                    <option value="{{ $operation->id }}">{{ $operation->translation->name }}</option>
                @endif
            @endforeach
        </select>

        @if ($errors->has('operation_id'))
            <div class="invalid-feedback">
                <strong>{{ $errors->first('operation_id') }}</strong>
            </div>
        @endif

Then the controller :

class OfferController extends Controller
{

use UploadTrait;


/**
 * Display a listing of the resource.
 *
 * @return \Illuminate\Http\Response
 */
public function index(Request $request)
{
  return view('dashboard.offers.index');
}

/**
 * Show the form for creating a new resource.
 *
 * @return \Illuminate\Http\Response
 */
public function create()
{
    $doctors = Doctor::get();
    $operations = Operation::with([
        'translation' => function($q) {
            return $q->where('language_code', app()->getLocale());
        }
    ])
    ->get();

    $hotels = Hotel::get();
    $currencies = Currency::get();

    return view('dashboard.offers.create', compact( 'doctors', 'operations', 'hotels', 'currencies'));
}

/**
 * Show the form for editing the specified resource.
 *
 * @param  Offer  $offer
 * @return \Illuminate\Http\Response
 */
public function edit(Offer $offer)
{
    $language = \App\Models\Language::where('language', request()->input('lang', env('APP_LANG', 'fr_FR')))->firstOrFail();

    $offer->load(['translations']);


    $doctors = Doctor::get();
    $operations = Operation::with([
        'translation' => function ($q) {
            return $q->where('language_code', app()->getLocale());
        }
    ])
    ->get();


    $hotels = Hotel::get();
    $currencies = Currency::get();

    return view('dashboard.offers.edit', compact('offer', 'doctors', 'operations', 'hotels', 'currencies', 'language'));

}

/**
 * Store a newly created resource in storage.
 *
 * @param  \Illuminate\Http\Request  $request
 * @return \Illuminate\Http\Response
 */
public function store(OfferRequest $request)
{
  $offer = Offer::create($request->only('price', 'hotel_included', 'recommended_stay', 'hospitalisation', 'visible', 'operation_id', 'doctor_id', 'hotel_id', 'hospitalisation', 'price_fixed', 'currency', 'promote', 'first_picture'));

  $offer->translations()->create([
      'language_code' => env('APP_LOCAL', app()->getLocale()),
      'title' => $request->title,
      'features' => $request->features,
  ]);

  $operationId = collect($request->input('operation_id'))->keys();
    $offer->operations()->attach($operationId);

  return redirect()->route('admin.offers.index')->with('success', 'Une nouvelle offre a été enregistrée');
}


/**
 * Update the specified resource in storage.
 *
 * @param  \Illuminate\Http\OfferRequest  $request
 * @param  OfferTranslation  $offerTranslation
 * @return \Illuminate\Http\RedirectResponse
 */
public function update(OfferRequest $request, Offer $offer)
{


    $offer->update($request->only('price', 'hotel_included', 'recommended_stay', 'hospitalisation', 'visible', 'operation_id', 'doctor_id', 'hotel_id', 'hospitalisation', 'price_fixed', 'currency', 'promote', 'first_picture'));

    $language = \App\Models\Language::where('language', request()->input('lang', env('APP_LANG', 'fr_FR')))->firstOrFail();


    $offer->translations()->updateOrCreate(
        ['offer_id' => $offer->id, 'language_code' => $language->language],
        $request->only('title', 'features')
    );

    $operationId = collect($request->input('operation_id'))->keys();
    $offer->operations()->sync($operationId);

    return redirect()->route('admin.offers.index')->with('success', "L'offre a été mise à jour");
}

When i try to update, i get this error :
SQLSTATE[HY000]: General error: 1366 Incorrect integer value: ‘[“1”]’ for column ‘operation_id’ at row 1 (SQL: update offers set operation_id = [“1”], offers.updated_at = 2022-05-30 14:56:42 where id = 1)

Message error

I don’t know from where come the error. Thank in advance of ur help