database question -> get rows from complex query AND results in ONE query ?!

[eluser]Richard Schumann[/eluser]
but why ? i have one query what i can split like

$this->db->from(‘user’);
$this->db->num_rows();

if ($search) { $this->db->like }
$this->db->where
and so on

and finaly get();

so why i cant do before a limit a count and then a offset get ?! :-)

i wonder if big projects or maybe google repeat the full code just for a resultcount :-(