In reply to Dave Garbutt.

The hash object is a very powerful tool, but of course it's memory intensive. For very large data it may not be feasible. It's good to have a variety of techniques in your "SAS programming quiver" to pull out as needed.

For those wanting to learn more about hash objects, Michele Burlew has a new book on the topic. She also has a free webinar in the SAS Talks series to introduce you to the hash object with some examples.