I am developing query / report from tfacp200 table.

selection from tfacp200 type,doc.no,doc.dt and tpay = 1 and amount.
record is appearing correctly. Invoice booked status.

now the invoice is linked and paid . and only unpaid/unlink document details require to define in query.

how to define??

Technically u can write a query to get balc / balh on header record. But good thing (depending on need for various parameters ) could be to write an AFS on tfacr2421m000 and get a balance from customer report.