Adding where clause to count_all

[eluser]Wonder Woman[/eluser]
Hi,

I basically just want to add a where clause to my count all request - is there anyway I can add this on to what I have?

I currently have:

Code:

$this->db->count_all('comments');

but I would typically like:

Code:

$this->db->count_all('comments')->where('approved', 1);

or something similar.

Any help would be appreciated.

Thanks.