Insert Row numbers in Invoice

[swaminathan]

How to Insert Row numbers in Invoice
I want to insert row numbers in invoice, as Sr.No for each item in invoice
I have tried to use salesorderdetails.orderlineno this suits my requirement, but he problem is -
When i insert the line -salesorderdetails.orderlineno in the SQL Query

// gather the invoice data

if($InvOrCredit=='Invoice') {
$sql = "SELECT debtortrans.trandate,
debtortrans.ovamount,
salesorderdetails.orderlineno
I get an SQL error saying unknown column in field list.

I tried -
$orderno = $myrow[orderno];

$result = DB_query("SELECT orderlineno
FROM salesorderdetails
WHERE orderno = " . $orderno );
$linecount = DB_fetch_array($result);
$orderlines = $Itemcount['orderlineno'];

this returns only one row from the salesorder I have four items in the order selected.

Result with echo statement- echo print_r( $linecount);
shows- Array ( [0] => 0 [orderlineno] => 0 )

how do I fetch all lines in order.

Please help