<?php
$a=mysql_result(mysql_query("SELECT COUNT(*) FROM `user` WHERE `date_last` > '".(time()-600)."' AND `url` like '/zagruz/%'"), 0);
$b=mysql_result(mysql_query("SELECT COUNT(*) FROM `guests` WHERE `date_last` > '".(time()-600)."' AND `url` like '/zagruz/%'"), 0);
$c=$a+$b;
echo "<a href='/zagruz/online.php'><font color='red'><b>$c</b></font> чел.</a>";
?>