Suppose I have this query:

SELECT a., b. FROM a JOIN b on a.id = b.id

When I call GetMulti() on A's collection, I can access A's entity fields. How do I access the entity fields from B?

Entities span 1 table for now (will change soon). So if you want fields from multiple entities, in your case a and b, create a typed list or a dynamic list. Please consult the documentation about typed lists for details.

Otis wrote:

Entities span 1 table for now (will change soon). So if you want fields from multiple entities, in your case a and b, create a typed list or a dynamic list. Please consult the documentation about typed lists for details.

Creating a view can also be an easy workaround.