Help with query: Join, Limit and Count total rows?

[eluser]Armchair Samurai[/eluser]
This will retrieve the first 20 posts with motorcycle tag as well as give the total number of 'motorcycle' posts contained in the database.

Code:

$data = new stdClass;

$this->db->start_cache();
    $this->db->from('posts p');
    $this->db->join('users u', 'p.userid = u.id');
    $this->db->join('tagmap tm', 'p.id = tm.post_id');
    $this->db->join('tags t', 'tm.tag_id = t.id');
    $this->db->where('t.name', 'motorcycles');
$this->db->stop_cache();

$data->count = $this->db->count_all_results();

$this->db->select('p.*, u.username');
$this->db->limit(20);

$query = $this->db->get();
$data->posts = $query->result();

$this->db->flush_cache();
return $data;