$this->db->select('startdate');
$this->db->from('db_dates');
$sdate = date("Y-m-d", strtotime(str_replace('-', '/', `startdate`)));
$timediff = abs(strtotime($sdate) - time());
$days     = floor($timediff/(60*60*24));
$where = "( noofdays = 0 OR ( noofdays >='".$days))";
$this->db->where($where);

SELECT startdate
FROM db_dates
WHERE ABS(DATEDIFF(STR_TO_DATE(startdate, '%m-%d-%Y'), CURDATE())) > noofdays