$this->db->having('y', 'year('.$date.')');

`y` =  'year(2014-2-1)'

$this->db->having('y', 'year('.$date.')',true);

y = year('2014-2-1')

`y` = year('2014-2-1')

`y` = year(2014-2-1)

$this->db->having("`y` = YEAR('".$date."')",null,FALSE);