Steve,

I think the best way to what you ask is by using MS Access. First you creat
a new database and then link the csv files (File == Get External == Link
Tables). Access will link to csv files very easily. Then create a query
that queries all 3 csv files. Now, you may have to get additional help from
the Access Users' Group. This approach should solve your problem.

John

"Steve Audus, Chaucer BEC, Sheffield UK" wrote:

We generate a csv file each night with over 10,000 records,
it's a list of classes, teachers and students.

Could anyone give me some advise on a easy way of automaticaly comparing the
one csv to another, and then creating a 3rd csv with just the differences?

Thank you for any help or advise.

Steve