<?php  include("includes/db_config.php"); 
if(isset($_POST["cidd"]))  
 {  $query = mysqli_query($conn,"SELECT SUM(total_amt) as ttl FROM sale_details WHERE customer_id = '".$_POST["cidd"]."'");
      $rows = mysqli_fetch_array($query); 
    $sql_query = mysqli_query($conn,"SELECT SUM(received_amonut) as rttl FROM ah_sales_payment_in WHERE customer_id = '".$_POST["cidd"]."'");
      $row = mysqli_fetch_array($sql_query);
      if(!empty($row['rttl'])){ 
      $data= "Rs: ". $rows['ttl'] - $row['rttl'];
       }else{
      $data= "Rs: ". $rows['ttl']; }
      echo json_encode($data);  
    //  echo json_encode(array("dsamt"=>"$dsamt"));  
 }  
 ?>