What I'd like to see is a universal SQL that can be translated to whatever dialect of SQL my current database is using. That way I won't have to relearn SQL every time I start a project with a different database engine.
If you're using Java (JDBC), there's an embedded kit so you don't have to run a standalone server. If you're not using Java, you can run the standalone server which also emulates the Postgres ODBC protocol so you can (for example) use `psql` to connect and run queries.