I have a database that includes both numeric and categorization
information about a set of retail stores. I want to create one
additional column in the database that represents the rank of each store
within its segment (i.e. the ranking for a numeric performance field
within the store's segment, as defined by one of the categorization
fields). I want the ranking to be in any of three possible forms -
either a numeric rank, or a percentile, or simple categorization (e.g.,
Top 20%, Bottom 80%).

I have not been able to figure out any way to do this other than by
manual, brute force - creating a page for each segment, calculating
rankings there, and then bringing results back to the main database by
formula. I have tried the percentile function - which appears to work on
an entire database, even if the database is filtered (not the way sums
and averages work). I have also hunted for database functions, but have
not found anything to do what I need.

Can anyone offer ideas on whether there is something other than my brute
force approach?

Thanks in advance