Sum attribute?

[AustinKleinberg]

I just installed ArcGIS Explorer, and I have a question. Is it possible to find all the values of a certain attribute? For example, I am using the National Hydrography Dataset (NHD), and queried for a certain stream. Now I want all the values for length in kilometers for that stream, so I can add them up and find the total length of the stream. I cannot figure out how to do it. Thoughts? Thanks in advance.

[DarrylDempsey]

Austin,
Here's an Addin we use which calculates statistics (count, min, max, sum(numbers), mean(numbers)) for columns in any map item with a table (including query results). Some obvious improvements would be:
- a more appropriate icon (Sigma?)
- using Julian Day Numbers to be able to calculate more than just min and max for date-time fields
- a frequency distribution graph as in ArcMap

The C# code is available if you want.

[AustinKleinberg]

That's great! Thanks, both of you!