Payables - Supplier Opening Credit - Debit - Net Amount Formula

/*******Supplier Opening Balance*******/

/*---------Net Opening Credit Balance----------*/
/*--------------NET_CR_OB----------------------*/

select nvl(sum(inv.invoice_amount *  nvl(inv.exchange_rate,1)) ,0)
from ap_invoices_all inv
where inv.vendor_id = :VENDOR_ID
and inv.gl_date < :P_FROM_DATE ;
   

/*---------Net Opening Debit Balance-----------*/
/*--------------NET_DR_OB----------------------*/    
   
select nvl(sum (chk.amount * nvl (chk.exchange_rate,1)) ,0)
from ap_checks_all chk
where chk.vendor_id = :VENDOR_ID
and chk.check_date < :P_FROM_DATE;

/*---------Net Opening Debit Balance-----------*/
/*-----NET_OB_BAL = NET_CR_OB - NET_DR_OB------*/

(select nvl(sum(inv.invoice_amount *  nvl(inv.exchange_rate,1)) ,0)
from ap_invoices_all inv
where inv.vendor_id = :VENDOR_ID
and inv.gl_date < :P_FROM_DATE )
    -
    (select nvl(sum (chk.amount * nvl (chk.exchange_rate,1)) ,0)
from ap_checks_all chk
where chk.vendor_id = :VENDOR_ID
and chk.check_date < :P_FROM_DATE )