Aggregate query with Castle ActiveRecord

Question

I'm trying to perform a simple aggregate query that returns the aggregate's result plus an extra column. This post -> Custom query with Castle ActiveRecord had a good example about how to achieve this, but I can't seem to get it to work. It seems that ActiveRecordMediator.ExecuteQuery returns an ArrayList of objects (instead of ArrayList of object[] which is what I would expect). Also if I try to cast it to ICollection I get a run-time error complaining of invalid cast. Code below, any help appreciated (don't want to use hand-written sql).

HqlBasedQuery query = new HqlBasedQuery(typeof(Something), @"select count(1),  
  p.Name from Something p 
  where p.SomeDate > :date
  order by p.Name
  group by p.Name");

query.SetParameter("date", new DateTime(2009, 1, 1));

var results = from summary in 
    (ICollection<object[]>)ActiveRecordMediator.ExecuteQuery(query)
    select new {
        Count = (int)summary[0], Name= (string)summary[1]
    };

The line after "from summary in" is the one that throws the invalid cast exception.

(Forgot to mention: using VS2008, .NET 3.5SP1, ActiveRecord 1.0RC3, NHibernate 1.2)

Answer 1

1. I think you meant count(*) instead of count(1) (this is why you're getting only 1-col rows)
2. ActiveRecordMediator.ExecuteQuery (at least in RC3) returns an ArrayList (not a generic ICollection) of object[]
3. Be careful casting count results as int. Some databases return counts as long (e.g. SQL Server)