NHibernate QueryOver Join to subquery

Question

Is there anyway to do a join to a select statement using NHibernate (QueryOver if possible)?

Here is the SQL I'm hoping to generate

SELECT r.MaxReading, r.MeterId, m.PreviousHours
FROM 
 Meters m
 LEFT JOIN
   (SELECT Max(mr.ReadingHours) as MaxReading, mr.AssetMeterId
    FROM MeterReadings mr
    WHERE mr.MeterId IN(1,2)
    GROUP BY mr.MeterId) r
 ON m.Id=r.MeterId

I did find this post, but it looks like the answer was to build a different query. Which makes me think this may not be possible.

I already figured out how to build the subquery piece, so any answer can just use a simple query in it's place as an example. Thanks!

Answer 1

As far as I know, it's impossible to join on a subquery in NHibernate since all joins must come from relations in your object model.