I'm trying to count the number of days left, NOTE: Due date is available in database, but number of days left not stored in the database
$sql="SELECT count(id) AS total FROM clients WHERE round((((strtotime.due_date-
time())/24)/60)/60))<=30";
$result=mysqli_query($con,$sql);
$values=mysqli_fetch_assoc($result);
$num_rows=$values['total'];
echo $num_rows ;