Thanks for your input.
I had a discussion about DSL earlier with some people. Personally, I think the best way to train people on how to use the CDM and the Vocabularies is to use SQL as this is the most expressive way. The SQL library will make the queries accessible for more people (you can replace the drug of interest etc) and moreover we have tools like Atlas that produces general results for users without SQL knowledge.
However, I am not a DSL expert nor user, so it may be valuable for others. I do think for the tool we are talking about now it is bit off an overkill indeed.
Peter