Join 3 tables

[Helge]

Hi

I'm having trouble getting data from three different tables. I have the following sturcture:

CREATE TABLE `attendee` (
  `id` int(11) NOT NULL default '0',
  `fisrtname` varchar(30) NOT NULL default '',
  `lastname` varchar(30) NOT NULL default '',
  `sex` enum('f','m') NOT NULL default 'k',
  `groupid` int(11) NOT NULL default '0',
  `roomid` int(11) NOT NULL default '0',
  PRIMARY KEY  (`id`)
) 

CREATE TABLE `group` (
  `id` int(11) NOT NULL auto_increment,
  `groupname` varchar(30) NOT NULL default '',
  `firstname` varchar(30) NOT NULL default '',
  `lastname` varchar(30) NOT NULL default '',
  PRIMARY KEY  (`id`)
)  

CREATE TABLE `room` (
  `id` nt(11) NOT NULL auto_increment,
  `roomnumber` varchar(10) NOT NULL default '',
  `type` enum('f','m') collate NOT NULL default 'k',
  `maxnumberofbeds` int(11) NOT NULL default '0',
  `leader` int(11) NOT NULL default '0',
  PRIMARY KEY  (`id`)
) 

I'm having the following query, but it returns an empty result set. I realise that joining table isn't my stength.

SELECT attendee.firstname
     , attendee.lastname
     , attendee.sex
     , group.firstname AS gfirstname
     , group.lastname AS glastname
     , room.nr AS room
  FROM attendee 
     , room
     , group
 WHERE attendee.groupid = group.id
   AND attendee.roomid = room.id
ORDER BY attendee.lastname ASC 

Any help is appreciated.

-Helge