where group codeigniter

$this->db->select('*')->from('my_table')
        ->group_start()
                ->where('a', 'a')
                ->or_group_start()
                        ->where('b', 'b')
                        ->where('c', 'c')
                ->group_end()
        ->group_end()
        ->where('d', 'd')
->get();

// Generates:
// SELECT * FROM (`my_table`) WHERE ( `a` = 'a' OR ( `b` = 'b' AND `c` = 'c' ) ) AND `d` = 'd'

$this->db->select('ae_users.employee_id, ae_users.emp_name, ae_users.emp_name2, ae_users.emp_name3');
		$this->db->from('ae_users');                
		$this->db->where_in('ae_users.employee_id',$employee_ids);
     
		$query =$this->db->get();
             
		if ($query->num_rows()) {
			return $query->result_array();
		} else {
			return 0;
		}

$data = array(
        'title' => 'My title',
        'name' => 'My Name',
        'date' => 'My date'
);

$this->db->insert('mytable', $data);
// Produces: INSERT INTO mytable (title, name, date) VALUES ('My title', 'My name', 'My date')