php - How to calculate Due Fees? -

i want calculate due fees, w.r.t current month. session of schools starts apr, , fees starts apr.

if student not pay fees in apr, may, jun, , paying fees in aug. due fees must apr + may + jun.

but i`m confused how due fees based on current month.

my code:

$current_month = date('m'); $final = 0; for($i='apr'; $i<$current_month; $i++) { $query_run = mysqli_query($conn,"select amount fees_on_class class = '$class'");  while ($num = mysqli_fetch_assoc ($query_run))  {     $temp += $num['amount']; }  $final = $final + $temp; } mysqli_query($conn,"insert dues(registration_number, due_fees)values('$registration_number','$final')"); 

code not working , giving 0 (0).

thanks.

alphabetic value in loop using not work want.

for($i='apr'; $i<$current_month; $i++) { } 

please make month loop numeric.

for($i='4'; $i<$current_month; $i++) { } 

i have not checked whole code, first error can see..