I need help fetching user group codes and then showing post for those groups with PHP and MySQL -

the code have works, there problem can't sort data id because of way it's fetching group codes. here's code:

function displayoverview(){    global $database;    global $session;    $q = "select username, group_code "    ."from classes username = '".$session->username."'";    $result = $database->query($q);    /* error occurred, return given name default */    $num_rows = mysql_numrows($result);    if(!$result || ($num_rows < 0)){       echo "error displaying info";       return;    }    if($num_rows == 0){       echo '<div id="container"><div id="float_left"><img src="profile_pics/default.gif" class="image3" width="50" height="50" border="0"></div>         <div id="float_right"><div id="container2"><div class="bubble">         <p class="user_name"></p>         <p class="time">error name | <?php echo date("f j, y, g:i a"); ?></p>         <p class="post">error messages.</p>         <!-- <p class="attachments"><img src="images/attachment.png" width="20" height="20"><b>attatchmentments</b><br></p> -->         </div></div></div></div>';       return;    }    /* display table contents */    for($i=0; $i<$num_rows; $i++){        $group_code = mysql_result($result,$i,"group_code");    $q2 = "select id, username, post, date, group_code, type, attachment_1, attachment_2 "    ."from posts group_code = '".$group_code."'";    $result2 = $database->query($q2);    /* error occurred, return given name default */    $num_rows2 = mysql_numrows($result2);    for($i2=0; $i2<$num_rows2; $i2++){        $uname2  = mysql_result($result2,$i2,"username");        $post = mysql_result($result2,$i2,"post");        $type = mysql_result($result2,$i2,"type");       $userinfo2  = $database->getuserinfo2($uname2);       $userinfo3  = $database->getuserinfo3($uname2);       $full_name = $userinfo2['full_name'];       $profile_img = $userinfo2['profile_img'];    }   } } 

i have stuck, there way retrieve group codes call mysql database , find out groups user in , return post groups

you can in 1 query, joining 2 tables this:

select   c.username,   c.group_code,   p.id,   p.post,    p.date,   p.type,   ... classes c inner join posts p on c.group_code = p.group_code c.username = ... order p.id;