Access 2010 offers something new called a CALCULATED FIELD where you can have a calculation performed in a TABLE. For example, let's say you're dealing with products. You have a UnitCost and a SalePrice. You can easily calculate your profit by saying SalePrice-UnitCost.

Now, those of you who know me and have taken my classes know that I abhor storing values in a table that you can use a QUERY to calculate. That's an easy calculation for a query. Storing needless data in your tables makes them big and slow.

HOWEVER...

There is always an exception to every rule. The major difference with Calculated Fields is that they can be used where you have really complex calculations AND you're running the query A LOT. With a Calculated Field, the RESULT of the calculation is actually stored in the table and is updated automatically whenever you modify one of the other fields that it depends on.

So, if you have a GIANT query with tens-of-thousands of records, and you run reports on this query ALL THE TIME, you might want to consider using a calculated field IF your database is running slow. Access doesn't have to perform all of those calculations EVERY TIME you run the query.

For the average database, I still maintain that keeping your calculations in a QUERY is better. But... it's my job to point out new things for you. If your giant queries are running REALLY slow and this might be the reason why, now you have a new tool in your arsenal to consider.

Enjoy!