DB to Excel (custom fields)

// Using https://github.com/PHPOffice/PHPExcel
<?php
require '/PHPExcel.php';
    class Db
    {
        public static function getConnection()
        {
            $params = array('host' => 'localhost', 'dbname' => 'korlabDB', 'user' => 'root', 'password' => '12345');
            $dsn = "mysql:host={$params['host']};dbname={$params['dbname']}";
            $db = new PDO($dsn, $params['user'], $params['password']);
            $db->exec("set names utf8");
            return $db;
        }
    }
    $db = Db::getConnection();
    $stmt = $db->prepare('select * from users');
    $stmt->execute();
    $data = [];
    $counter = 0;
    echo $res['id'];
    while($res = $stmt->fetch(PDO::FETCH_ASSOC)){
        $data[$counter]['id'] = $res['id'];
        $data[$counter]['username'] = $res['username'];
        $data[$counter]['email'] = $res['email'];
        $data[$counter]['name'] = $res['name'];
        $data[$counter]['surname'] = $res['surname'];
        $data[$counter]['middlename'] = $res['middlename'];

        $data[$counter]['specialty_1'] = $res['specialty_1'];
        $data[$counter]['zno_competition_score_1'] = $res['zno_competition_score_1'];
        $data[$counter]['priority_1'] = $res['priority_1'];

        $data[$counter]['specialty_2'] = $res['specialty_2'];
        $data[$counter]['zno_competition_score_2'] = $res['zno_competition_score_2'];
        $data[$counter]['priority_2'] = $res['priority_2'];

        $data[$counter]['specialty_3'] = $res['specialty_3'];
        $data[$counter]['zno_competition_score_3'] = $res['zno_competition_score_3'];
        $data[$counter]['priority_3'] = $res['priority_3'];

        $counter++;
    }

    $objPHPExcel = new PHPExcel();
    $objPHPExcel->getProperties()->setCreator("MRPL-server")
                             ->setLastModifiedBy("MRPL-server")
                             ->setTitle("Users")
                             ->setSubject("users feedback")
                             ->setDescription("Description")
                             ->setKeywords("office 2007 openxml php")
                             ->setCategory("result file");
    $objPHPExcel->setActiveSheetIndex(0)
        ->setCellValue('A1', 'id')
        ->setCellValue('B1', 'Имя пользователя')
        ->setCellValue('C1', 'Email')
        ->setCellValue('D1', 'Имя')
        ->setCellValue('E1', 'Фамилия')
        ->setCellValue('F1', 'Отчество')

        ->setCellValue('G1', 'Специальность №1')
        ->setCellValue('H1', 'Конкурсный балл №1')
        ->setCellValue('I1', 'Приоритет №1')

        ->setCellValue('J1', 'Специальность №2')
        ->setCellValue('K1', 'Конкурсный балл №2')
        ->setCellValue('L1', 'Приоритет №2')

        ->setCellValue('M1', 'Специальность №3')
        ->setCellValue('N1', 'Конкурсный балл №3')
        ->setCellValue('O1', 'Приоритет №3');
    for($i = 0; $i<count($data); $i++ ){
        $j = $i + 2;
        $objPHPExcel->setActiveSheetIndex(0)
            ->setCellValue('A'.$j, $data[$i]['id'])
            ->setCellValue('B'.$j, $data[$i]['username'])
            ->setCellValue('C'.$j, $data[$i]['email'])
            ->setCellValue('D'.$j, $data[$i]['name'])
            ->setCellValue('E'.$j, $data[$i]['surname'])
            ->setCellValue('F'.$j, $data[$i]['middlename'])

            ->setCellValue('G'.$j, $data[$i]['specialty_1'])
            ->setCellValue('H'.$j, $data[$i]['zno_competition_score_1'])
            ->setCellValue('I'.$j, $data[$i]['priority_1'])

            ->setCellValue('J'.$j, $data[$i]['specialty_2'])
            ->setCellValue('K'.$j, $data[$i]['zno_competition_score_2'])
            ->setCellValue('L'.$j, $data[$i]['priority_2'])

            ->setCellValue('M'.$j, $data[$i]['specialty_3'])
            ->setCellValue('N'.$j, $data[$i]['zno_competition_score_3'])
            ->setCellValue('O'.$j, $data[$i]['priority_3']);
    }

    $objPHPExcel->getActiveSheet()->setTitle('Simple_clean');

    $objPHPExcel->setActiveSheetIndex(0);
    $objPHPExcel->getActiveSheet()->getColumnDimension('A')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('B')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('C')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('D')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('E')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('F')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('G')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('H')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('I')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('J')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('K')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('L')->setAutoSize(true);
    $objPHPExcel->getActiveSheet()->getColumnDimension('M')->setAutoSize(true);

    header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
    header('Content-Disposition: attachment;filename="Report.xlsx"');
    header('Cache-Control: max-age=0');

    $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007');
    $objWriter->save('php://output');
    echo "ok";
?>