Все просто
PHP код:
insert_recordset tmp_Table (TransTableID,TransRecID)
select TransTableID from MarkUpTrans
join RecId from VendInvoiceTrans
WHERE VendInvoiceTrans.InvoiceId == "XXX" &&
MarkUpTrans.TransRecId == VendInvoiceTrans.RecId;
join Table = join * from Table, а Вам надо всего 2 поля