Roman, currently the answer is no. To access data in a SQL database stored in AWS, e.g. a Postgres RDS instance, you would need to create a REST API on, say, EC2 to securely allow access into the desired SQL database’s tables, authenticating requests as appropriate. One approach to doing this is to use something like PostgREST, which automatically generates a sophisticated REST API around selected PostgreSQL tables and provides extremely past performance: http://postgrest.com/en/v0.4/
A generic SQL Data Source Type is, however, on the Skuid product roadmap, so stay tuned.
