namespace IOT{
　　public class CustomerProjection{
　　　　public int ID = 0;
　　　　public string Name = "";
　　　　public CustomerProjection(int id, string name){
　　　　　　ID = id;
　　　　　　Name = name;
　　　　}
　　}
}

[Imprt(typeof(IOT.CustomerProjection), "CustomerProjection")]
[ActiveRecord("Customers")]
public class Customer : ActiveRecordBase<Customer>
{
     [PrimaryKey(PrimaryKeyType.Assigned)]
    public string CustomerID
    {
        get { return customerID; }
        set { customerID = value; }
    }
    .....
 }

protected void Page Load(object sender, EventArgs e)
{
    IActiveRecordQuery query = new HqlBasedQuery(typeof (Customer),
        @"select new CustomerProjection(c.CustomerID, c.CompanyName)
             from Customer c join c.Orders o where c.Country = 'USA'
           group by c.CustomerID, c.CompanyName, c.City, c.Region
");
    GridView1.DataSource = ActiveRecordMediator.ExecuteQuery(query);
    GridView1.DataBind();
}