How do I allow users to search a database table?

I recently launched the new Rails-based version of Doppler Value
Investing
(http://www.dopplervalueinvesting.com). It profiles over 4000
individual
stocks in terms of free cash flow and net liquid assets.

As you can see at http://dopplervalueinvesting.com/stocksview, I know
how
to extract data from a table in a Postgres database and display it to
users.

However, I’m looking for a way to provide a search form that allows
users
to create their own custom search of the stock database table and see
their
results. Where can I find a good example of this?

You might want to look at one or another of the search helper gems. This
one is nice: Project: meta_search - The Ruby Toolbox
Basically, any of these will extend ActiveRecord to give your views the
ability to construct custom search queries. This can be used to make
really detailed search forms that essentially reflect over your database
structure.

Walter