How to seperate database queries?

[eluser]Unknown[/eluser]
SOLVED

Hello I've queries such as

Code:

function blablabla(){

$this->db->where('username', $username);
$this->db->where('password', $password);
$this->db->from('users');

return ($this->db->count_all_results() > 0);
}

But I'm using this function more than two times and I see that It creates a sql query on third use such as:

Code:

...WHERE username=something AND password=something AND username=something AND password=something AND username=something AND password=something

I want to reset previous query data in $this->db on the next query but how can I do that?

Thanks.[/b]

[eluser]Unknown[/eluser]
Solved.