Ask HN: Resources for creating business intelligence features for a Rails app

I have a small SaaS app built in Rails, and my customers are asking for what I think would be described as business intelligence features. They want to see statistics about their data and usage.

I'm able to get the answers they are looking for using SQL, but as far as making it performant and user-ready, I'm not sure the best way to go about it. Can anyone point me to a good resource on implementing this correctly? I need to be able to do things like sort a list by most popular within a time range, run calculations for each row in a list and provide the output to a table, etc.