Confluent has recently released another version of KSQL, or should I say the aptly renamed ksqlDB.  It is currently community licensed and fully available on Github (https://github.com/confluent/ksql).  Whether you currently have a Kafka instance up and running or not, you can be up and running with this on Docker Compose fairly quickly if you wanted to try some things out on a VM.

Two of the main features it boasts are pull queries and connector management.

A pull query is a form of  query issued by a client that retrieves a result as of "now," like a query against a traditional RDBS.  Pull queries have limitations ANSI SQL  does not, but nevertheless, potentially greatly simplify the architecture of typical stream processing use cases.

A pull query has the following general structure:

SELECT select_expr [...]
    FROM aggregate_table
    WHERE ROWKEY=key
    [AND window_bounds];

As aforementioned, ksqldb also integrates with Kafka Connect as well as create and manage connectors.

I look forward to taking more time to test out these features, and I'm already anxious for the next release.

you can find great documentation on ksqldb at:

https://docs.ksqldb.io