num_rows() problem

[eluser]eldrinofsoalim[/eluser]
Hi guys, I have a problem with this code:

if ($this->session->userdata('username') == "" ) { echo "Blank"; } else { echo "Not Blank"; }

$query1 = $this->db->get_where('users', array('username' => $this->session->userdata('username')));
print_r ($query1->num_rows());

$query2 = $this->db->get_where('users', array('username' => ""));
print_r ($query2->num_rows());

It produces this output:

Blank<br />
1 <br />
0

My 'username' cookie is empty or blank (as shown in first line of code). HOWEVER, whenever I use the Active Records get_where() function, where table name is 'users' and where field name 'username' is equal to the username cookie (remember, it's blank), it always returns 1.

Why does it return 1 when there is no blank username in the table?

Hoping for your help.

eldrinofsoalim