Acummulating a total using two files

Question

I have two files that I am working with. One file is a lsit
of all our customer orders that contains basic data that has been
estimated. The second file I have is sorted by order number (the
same key as file one) and contains multiple records for each order
that is created once the actual order has been billed. And in the
event that credits or additions to that same order take place, the
number of records for each order number will increase in that
second file.
What I want to do is to move through a recordset that is
based on file one. As each record of that recordset is read I want
a specific field (amount due) to be subject to logic whereby file 2
is checked to see if an order number exists, and if it does, a loop
is performed accumulating a total (amount due) until such time as
all records for that order number have been read. I will then
<cfoutput> the data records for recordset one from file one
with either the estimated or actual amount due.
On our AS400 I know the programmers can set a lower limit to
get right to the beginning of the data that is sought. I would be
very interested in any ColdFusion technique that is recommended
that can accomplish the same thing. I am also thinking that
<cfbreak> could be utilized within a loop to quickly exit the
sorted list once the order number changes.
I will be creating a list of two thousand records, so getting
this program to run as quickly/efficiently as possible is
important. Else the program will not be used by our staff. I would
be very appreciative of recommendations on the best methods to
accomplish what I have outlined. Thank you

Answer 1

I have arrived at a partial solution based on your (very
appreciated) advice that I use a query of query. The following is
the last of 4 recordsets that I used to get my data. However,
because in the WHERE clause I ask for matching B/L (order) numbers,
I do not get a full data listing. (Yet I need the mutual primary
key for each file). What I need are all of the records from
Recordset2 and only those from Recordset3 that have a matching
B/L#. I do not want to lose records just because the order has not
yet been billed. What else do I need to implement? Thanks!
<cfquery name="Recordset4" dbtype="query">
SELECT Recordset3.RBLNO as BL, ((Recordset3.RCUTR - 100) /
100) as CUT,(Recordset2.DTAMTsum * -1) as LH, (Recordset2.DTAMTsum
* ((Recordset3.RCUTR - 100) / 100)) as NET
FROM Recordset3, Recordset2
WHERE Recordset3.RBLNO = Recordset2.DTBLNO
</cfquery>