Get ID from url to insert to WhereIn (Laravel)

I insert the url like this: "export/1-2-18". 1, 2, 18 are ids of table. The ID is checked by checkbox so, it can be any numbers on the table

The href like this

<a href ="{{ url('export',['id'=> $a ]) }}" class="btn btn-info export" id="export-button"> Export file </a> 

with $a = 1-2-18;

And this is the controller

public function exportFile($id){
            $rp = str_replace('-',',',$id);
            echo ($rp);
            $products = DB::table('duan')
                ->whereIn('MaDA', [$rp])
                ->get(); 
            dd($products);
            $products= json_decode( json_encode($products), true);
            return Excel::create('ThongTinDuAn', function($excel) use ($products) {
                $excel->sheet('sheet name', function($sheet) use ($products)
                {
                    $sheet->fromArray($products);
                     $sheet->getStyle('A2:E2')->getAlignment()->setWrapText(true);
                });

            })->export('xlsx');
        }  

I have replaced the url from "1-2-18" to "1,2,18" and insert to whereIn but I just received one of the results.

How to get all of the results? Thanks in advance.

2nd parameter for whereIn is wrong. You have to input array of values not an array with a string (['1,2,18'] should be [1,2,18]).

You can use explode() method.

$rp = explode('-',$id);
$products = DB::table('duan')
            ->whereIn('MaDA', $rp)
            ->get();