不将整个表下载为.csv文件只导出10条记录（laravel 5.3）

I am working to export data as csv its downloading only 1st 9 records total 10 on excel 1st is heading and 9 records then i want to export whole table from Db don't know whats gone wrong here is method below

public function ExportAll(){
      $student = Students::all();
$temp = tmpfile();
$heading = array('Name', 'Group');
fputcsv($temp, $heading);
foreach($student as $row) {
    fputcsv($temp, array($row['name'],$row['group']));
    }
    fseek($temp, 0);
        echo fread($temp, 1024);
        header('Content-Type: text/csv; charset=utf-8');
        header('Content-Disposition: attachment; filename=Student.csv' );
        fclose($temp);
        die;
    }

Its downloading only one row i want to download whole table usig this method Please help to fix route is as

Route::get('/student/ExportAll', 'StudentController@ExportAll');

here i have link to export as

<a href="/student/ExportAll">Export</a>

You are overwriting $values each time through the array.

$values = [];
foreach($student as $row) {
    $values[] = array($row['name'],$row['group']);
}