Libby Miller has announced an alpha release of Squish, which allows complex queries to be made on RDF through Java RDF APIs, such as Melnik's Stanford API or Jena.

Miller describes that language as:

... similar in some aspects to that used by R.V. Guha's rdfDB, and allows you to make complex queries of RDF models instead of navigating incrementally around them.

The syntax itself looks pretty much like SQL:

SELECT variables 
[FROM url, url] 
WHERE (pred variable/string variable/string) ... () () 
[AND constraint] 
[USING predString FOR predUrl] 

Squish also has a JDBC interface to enable querying of RDF stored in Postgres SQL databases or in-memory models. The demonstration software that comes with the release, based around Java servlets, enables the generation, query and display of RSS 1.0 channels.

Underlining that this is experimental technology, Miller adds:

This implementation is intended to demonstrate the possibilities of this approach, and is only appropriate for extremely small scale use. Comments are very welcome.