Use old "sales quantity" fields to predict next years likely quan

[The parawon]

Is there a way to have a calculated field create a forecast from two or other
three previous years sales quantity? For example, if I have 2002,2003,2004
(each year in a seperate field) and I want to use a forecast to tell what
2005 and 2006's sales' quantity (each in seperate fields) are likely to be?
Any help in the right direction would be very appreciated.

 

[MGFoster]

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First off, your table isn't in normal form, which makes it harder to
write a query. Change your table design to something like this:

CREATE TABLE Sales (
[year] int not null ,
sales money not null ,
... other columns if required ...
)

Forecasts are usually calculated by applying the increase/decrease in
sales, over a range, to the future range. E.g.:

Year Sales Change Forecast
==== ===== ====== ========
2002 25.00 0 0
2003 75.00 50 125 (50 + 75)
2004 100.00 25 125 (100 + 25)

To get this use a query like this:

SELECT [year], sales,
sales - (SELECT sales FROM Sales WHERE [year] = [year]-1) AS Change,
sales + Change As Forecast
FROM Sales
WHERE < criteria >

There probably are more sophisticated forecasts algorithm. You could
search on Google to find them.
--
MGFoster:::mgf00 <at> earthlink <decimal-point> net
Oakland, CA (USA)

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