How to get blob data in json or xml format?

I have stored xml file in mysql BLOB datatype,so now i want to get that data in xml or json format and need to display.

i tried like this,but getting binary values

  $mqs = db_select('multiple','mq')
     ->fields('mq',array('data'))
     ->condition('tokenid', '1')
     ->execute();
    foreach ($mqs as $row) {
        $test = base64_encode($row->surveyid);  //here junk binary data displaying 
            drupal_set_message("data ::".$test);
                $xml = simplexml_load_string($test);
                $json = json_encode($xml);
                $array = json_decode($json,TRUE);
            drupal_set_message("data::".$json);         
    }

actual data not displayed in XML or JSON formats?

any other alteatives?