Laravel 如何防止在选择多个选项时创建多个id？

当我在选择框中选择多个选项时，它会使多个id存储在不同的id中。我想将所有选定的选项存储在一个id中

这是我的创建表单

<form method="post" action="{{route('assignments.store')}}">
        @csrf
        <table>
                <tr>
                    <td>Task Title : </td>
                    <td>
                        <select name="task_id" id="task_id">
                            @foreach ($tasks as $task)

                                <option value="{{ $task->id }}">{{ $task->title }}</option>

                            @endforeach
                        </select>
                    </td>
                </tr>
                <tr>
                    <td>Staff Name : </td>
                    <td>
                        <select name="staff_id" id="staff_id" multiple>
                            <option value=''>Select One</option>
                            @foreach ($staffs as $staff)

                                <option value="{{ $staff->id }}">{{ $staff->name }}</option>

                            @endforeach
                        </select>
                    </td>
                </tr>
                <tr>
                    <td>Done At :</td>
                    <td><input type="time" name="done_at" class="form-control"></td>
                </tr>
            <td><button class="btn btn-primary" name="submit" type="submit" value="submit" id="submit">Submit</button></td>
        </table>
    </form>

---

所以您需要将任务id和员工id的所有组合存储为分配？

public function store(Request $request)
{
    $request->validate([
        // 'staff' => 'array|required',
        'staff_id' => 'required',
        'task_id' => 'required',
        'done_at' => 'sometimes',
    ]);
        $assignment = Assignment::create([
            'task_id' => $request->input('task_id'),
            'staff_id' => $request->input('staff_id'),
            'done_at' => 'null',
        ]);
        return redirect()->route('assignments.index', compact('assignment'))->withSuccess('Done');
}