Forwarding balance for running sum

[Anne]

I created this query with a running sum, which is sorted by date then by
transaction number. I put this into a form for entering transactions for an
investment money market account. It works very well.

However, now that I have one years worth of data in there, I would like to
limit the data for the form as well as for reports. As soon as I limit the
data range, I loose the beginning balance.
Can anybody give me an idea on how I could create a beginning balance when I
select a date range or a starting date?

 

[Anne]

While searching the internet for a solution, I found a similar post as mine
with an answer from Marshal Barton, who suggested creating a temporary table.

I already had a running sum total using DSum. In the query I create a field
which could give me the previous balance, which is the current running
balance less the transaction amount: PriorBal: [RunBal]-[TransAmount]

Upon opening the form, a make table query creates a temporary table with the
running balance everytime the form is opened. This table is used for the
reports. In the form header I show a text box with the "PriorBal" and it
looks really good.