Grouping NHibernate query results by nullable integer

I'm using NHibernate to query a table that has tuples in the format: (String, Int?), where the integers can be null. So, I want to group my results by number and then sort alphabetically. I can easily do this after I get the query results, but I would like to get NHibernate to formulate a query that does it. Here's an example of the results I would like:

alpha, 1

delta, 4

golf, 3

hotel, 2

lima, 5

charlie, 0

theta, 0

beta, null

echo, null

The three groupings I'm looking for are: (int > 0), (int == 0), and (int = null). Here's the query I'm using:

var devices = session.QueryOver<Table>()
                .OrderBy(item => item.Number).Desc
                .OrderBy(item => item.Name).Asc
                .List();

Currently, I'm sorting them after the query is done, as such:

List<Table> sortedDevices = devices.OrderBy(item => item.Name).Where(item => item.Number > 0).ToList();
            sortedDevices = sortedDevices.Concat(devices.OrderBy(item => item.Name).Where(item => item.Number == 0).ToList()).ToList();
     开发者_Go百科       sortedDevices = sortedDevices.Concat(devices.OrderBy(item => item.Name).Where(item => item.Number == null).ToList()).ToList();

Is it possible to get NHibernate to group queries like this?

---

something along the lines:

session.QueryOver<User>()
    .Select(Projections.Alias(Projections
        .Conditional(Expression.Gt("Number", 0),
            Projections.Constant(1),
            Projections.Conditional(Expression.Eq("Number", 0),
                Projections.Constant(0),
                Projections.Constant(-1))),
        "group"))
    .OrderBy(Projections.Property("group")).Desc
    .ThenBy(table => table.Name).Asc
    .List();