title: Unable to resolve NULL driver for [Maatwebsite\Excel\Transactions\TransactionManager]
body: <p>I am trying to download data from database to excel file. I have import the Maatwebsite\Excel from composer also.
  my code in my controller is:</p>
  
  <pre><code>function excel()
      {
  $month = date('m');
  DB::statement("CREATE OR REPLACE VIEW monthly_cost AS
  select  user_name,  id, phone, sum(cost) as cost from (
          select users.name as user_name, users.roll as id,users.phone as phone, BC.individual_cost as cost
          from breakfast_orders BO, breakfast_costs BC,users
          WHERE (BO.date=BC.date) and (BO.user_id=users.id)and MONTH(BO.date)='$month'
          UNION ALL
          select users.name as user_name, users.roll as id,users.phone as phone, LC.individual_cost as cost
          from lunch_orders LO, lunch_costs LC,users
          WHERE (LO.date=LC.date) and (LO.user_id=users.id) and MONTH(LO.date)='$month'
          UNION ALL
          select users.name as user_name, users.roll as id,users.phone as phone, DC.individual_cost as cost
          from dinner_orders ddO, dinner_costs DC,users
          WHERE (ddO.date=DC.date) and (ddO.user_id=users.id) and MONTH(ddO.date)='$month'
              ) x group by id,user_name,phone");
  
       $customer_data=DB::table('monthly_cost')-&gt;get()-&gt;toArray();
       $customer_array[] = array('Name', 'ID', 'Phone', 'Cost', 'Month');
       foreach($customer_data as $customer)
       {
        $customer_array[] = array(
         'Name'  =&gt; $customer-&gt;user_name,
         'ID'   =&gt; $customer-&gt;id,
         'Phone'    =&gt; $customer-&gt;phone,
         'Cost'  =&gt; $customer-&gt;cost,
         'Month'   =&gt; $month
        );
       }
       Excel::create('Customer Data', function($excel) use ($customer_array){
        $excel-&gt;setTitle('Customer Data');
        $excel-&gt;sheet('Customer Data', function($sheet) use ($customer_array){
         $sheet-&gt;fromArray($customer_array, null, 'A1', false, false);
        });
       })-&gt;download('xlsx');
      }
  </code></pre>
  
  <p>what should I do now?</p>