NHibernate QueryOver: How to join unrelated entities?

I have the following query working which gets the results I want:

int associatedId = 123;

MyObject alias = null;

var subQuery = QueryOver.Of<DatabaseView>()
    .Where(view => view.AssociatedId == associatedId)
    .And(view => view.ObjectId == alias.ObjectId)
    .Select(view => view.ObjectId);

var results = session.QueryOver<MyObject>(() => alias)
    .WithSubquery.WhereExists(subQuery)
    .List();

The DatabaseView has been mapped as an actual NHibernate entity (so I can use it with QueryOver), but it is not associated to MyObject in the HBM mappings.

This query returns an IList<MyObject> using a SELECT ... FROM MyObject WHERE EXISTS (subquery for DatabaseView here). How can I re-write this to return the same data but using a JOIN instead of sub query?