Change the value after expiration date PHP MYSQL -

i'm beginner in php mysql, have system after register/add customer information change status after 30 days.

scenario
in add customer page, have forms date start, date expiration , status.

date start - automatically set date today
expiration - automatically set date start + 30 days
expiration2 - automatically set expiration date + 90 days
status - status of customer (if newly registered status value fresh if after 30days status change inactive if after 90days change dormant.

this code datestart , dateexpired , dateexpired2 don't know how code status process.

$datestart= date('y-m-d'); $dateexpired = date('y-m-d', strtotime($datestart. ' + 30 days')); $dateexpired2 = date('y-m-d', strtotime($dateexpired2. ' + 90days'));  echo '<input type="text" name= "datestart" value="'. $datestart.'"/>'; echo '<input type="text" name= "dateexpired" value="'. $dateexpired .'"/>'; 

if run script @ scheduled interval, can automatically update user's status':

$datestart= date('y-m-d'); $dateexpired = date('y-m-d', strtotime($datestart. ' + 30 days')); $dateexpired2 = date('y-m-d', strtotime($datestart. ' + 90days'));  $status = "fresh";  if(strtotime($datestart)<strtotime('-30 days')){    $status = "inactive"; }  if(strtotime($datestart)<strtotime('-90 days')){    $status = "dormant"; }  //run sql update query set status 

see here sql update query