Function to get the customer balance by passing customer id,invoice currency code,gl date as parameters in 11.5.10.2

CREATE OR REPLACE function getcusbal(p1 in number,p2 in varchar2,p_date in date)
return number as
v_cus_bal number;
begin
SELECT NVL(SUM(NVL(amount_due_

remaining,0)),0)
       INTO v_cus_bal
      FROM ar_payment_schedules
       WHERE customer_id = p1
       AND invoice_currency_code = P2
       AND gl_date <= p_date
       AND NVL(receipt_confirmed_flag,'Y')='Y';
return v_cus_bal;
end;
/