Display recent user updates form two tables

[eluser]ram reddy[/eluser]
its working for me

$query1 = $this->db->get('Example_Table1');
$join1 = $this->db->last_query();
$query2 = $this->db->get('Example_Table2');
$join2 = $this->db->last_query();
$union_query = $this->db->query($join1.' UNION '.$join2.' ORDER BY column1,column2);