várias tabelas SQL com PHP para gerar mapa do site

while ($row = mysql_fetch_array($result))
{  
    $i_url = SITE_URL.'loja/'.$row['slug_title'];
    $year = substr($row['added'],0,4);
    $month  = substr($row['added'],5,2);
    $day  = substr($row['added'],8,2);
    $i_date = ''.$year.'-'.$month.'-'.$day.'';

    $data = subquery('what i need here', 'another param');

    echo  
    '
    <url>
    <loc>'.$i_url.'</loc>
    <lastmod>'.$i_date.'</lastmod>
    <changefreq>daily</changefreq>
    <priority>0.8</priority>
    </url>
    ';
}

function subquery($firstparam, $secondparam)
{
  $myquery = "SELECT * FROM ".$firstparam;
  //more code

  $result = 'my query result';

  return $result;
}