Query

CREATE TABLE `posts` (
  `ID` int(11) NOT NULL auto_increment,
  `threadID` int(11) NOT NULL default '0',
  `titel` text NOT NULL,
  `bericht` text NOT NULL,
  `poster_naam` text NOT NULL,
  `poster_email` text NOT NULL,
  PRIMARY KEY  (`ID`)
) TYPE=MyISAM AUTO_INCREMENT=6 ;

INSERT INTO `posts` VALUES (1, 1, 'Post1', 'Post1', '', '');
INSERT INTO `posts` VALUES (2, 1, 'Post2', 'Post2', '', '');
INSERT INTO `posts` VALUES (4, 1, 'Post4', 'Post4', '', '');

CREATE TABLE `posts` (
  `ID` int(11) NOT NULL auto_increment,
  `threadID` int(11) NOT NULL default '0',
  `titel` text NOT NULL,
  `bericht` text NOT NULL,
  `poster_naam` text NOT NULL,
  `poster_email` text NOT NULL,
  PRIMARY KEY  (`ID`)
) TYPE=MyISAM AUTO_INCREMENT=6 ;
 
INSERT INTO `posts` VALUES (1, 1, 'Post1', 'Post1', '', '');
INSERT INTO `posts` VALUES (2, 1, 'Post2', 'Post2', '', '');
INSERT INTO `posts` VALUES (4, 1, 'Post4', 'Post4', '', '');

CREATE TABLE `threads` (
  `ID` int(11) NOT NULL auto_increment,
  `categorieID` int(11) NOT NULL default '0',
  `titel` text NOT NULL,
  `bericht` text NOT NULL,
  `poster_naam` text NOT NULL,
  `poster_email` text NOT NULL,
  PRIMARY KEY  (`ID`)
) TYPE=MyISAM AUTO_INCREMENT=6 ;

INSERT INTO `threads` VALUES (1, 1, 'thread 1', 'thread 1 bericht', 'Fenrir', 'fenrir.jules@gmail.com');
INSERT INTO `threads` VALUES (2, 1, 'thread 2', 'thread 2 bericht', 'Fenrir', 'fenrir.jules@gmail.com');
INSERT INTO `threads` VALUES (4, 2, 'thread 4', 'thread 4 bericht', 'Fenrir', 'fenrir.jules@gmail.com');
INSERT INTO `threads` VALUES (3, 2, 'thread 3', 'thread 3 bericht', 'Fenrir', 'fenrir.jules@gmail.com');
INSERT INTO `threads` VALUES (5, 1, 'thread5', 'thread5', '', '');

CREATE TABLE `threads` (
  `ID` int(11) NOT NULL auto_increment,
  `categorieID` int(11) NOT NULL default '0',
  `titel` text NOT NULL,
  `bericht` text NOT NULL,
  `poster_naam` text NOT NULL,
  `poster_email` text NOT NULL,
  PRIMARY KEY  (`ID`)
) TYPE=MyISAM AUTO_INCREMENT=6 ;
 
INSERT INTO `threads` VALUES (1, 1, 'thread 1', 'thread 1 bericht', 'Fenrir', 'fenrir.jules@gmail.com');
INSERT INTO `threads` VALUES (2, 1, 'thread 2', 'thread 2 bericht', 'Fenrir', 'fenrir.jules@gmail.com');
INSERT INTO `threads` VALUES (4, 2, 'thread 4', 'thread 4 bericht', 'Fenrir', 'fenrir.jules@gmail.com');
INSERT INTO `threads` VALUES (3, 2, 'thread 3', 'thread 3 bericht', 'Fenrir', 'fenrir.jules@gmail.com');
INSERT INTO `threads` VALUES (5, 1, 'thread5', 'thread5', '', '');

SELECT
threads.ID as ID,
threads.titel as titel,
COUNT(posts.ID) as posts
FROM threads
LEFT JOIN posts
ON posts.threadID=threads.ID
WHERE threads.categorieID='.$ID.'
GROUP BY posts.threadID
ORDER BY threads.titel

SELECT
threads.ID as ID,
threads.titel as titel,
COUNT(posts.ID) as posts
FROM threads
LEFT JOIN posts
ON posts.threadID=threads.ID
WHERE threads.categorieID='.$ID.'
GROUP BY posts.threadID
ORDER BY threads.titel

array (
  0 =>
  array (
    'ID' => '1',
    'titel' => 'thread 1',
    'posts' => '3',
  ),
  1 =>
  array (
    'ID' => '2',
    'titel' => 'thread 2',
    'posts' => '0',
  ),
)

array (
  0 =>
  array (
    'ID' => '1',
    'titel' => 'thread 1',
    'posts' => '3',
  ),
  1 =>
  array (
    'ID' => '2',
    'titel' => 'thread 2',
    'posts' => '0',
  ),
)

array (
  0 =>
  array (
    'ID' => '1',
    'titel' => 'thread 1',
    'posts' => '3',
  ),
  1 =>
  array (
    'ID' => '2',
    'titel' => 'thread 2',
    'posts' => '0',
  ),
  2 =>
  array (
    'ID' => '5',
    'titel' => 'thread5',
    'posts' => '0',
  ),
)

array (
  0 =>
  array (
    'ID' => '1',
    'titel' => 'thread 1',
    'posts' => '3',
  ),
  1 =>
  array (
    'ID' => '2',
    'titel' => 'thread 2',
    'posts' => '0',
  ),
  2 =>
  array (
    'ID' => '5',
    'titel' => 'thread5',
    'posts' => '0',
  ),
)