Forum OpenACS Q&A: Do you know of a query-by-example web based tool?

I am looking for a tool, html and javascript on the client and I
don't care what on the server, that implements a query by example
interface to a database.  I would really like an opensourced
solution, but since I can't find any leads on this at all, I am
curious what is available in *any* form.

Does anyone know of one for PostgreSQL (or Oracle?)?

What kinds of html & javascript query tools are available?