How do you do a union of two tables in NHibernate?

Question

I need to do a union of two tables using NHibernate and HQL. I have found very little help online, and I want to know if it is possible and if so how?

Answer 1

Found my answer:

http://www.hibernate.org/117.html#A21

It doesn't currently support union or intersect.

Answer 2

I don't believe HQL supports unions, but you can write your own record transformer and author the sql by hand.

Answer 3

You could use a named sql-query and do the union in raw SQL. NHibernate will be able to populate entity instances from the sql-query and return those as the query result. See here and here.