Most of your favorite languages have sql composition libraries that'll get you 90% of this (Arel for Ruby, SqlAlchemy for Python, etc, etc).

The remainder, the "piping" syntax, is pretty easy to implement (Takes about 30-40 lines of ruby on top of Arel, speaking from experience).

So then, is this just a matter of wrapping a library in a web page and calling it SAAS? Or am I just totally missing the point?