DevExpress XPO with subselects

Question

I've broke my mind trying to write next MSSQL query using XPO:

SELECT     Gate.Name, grp.maxDate as 'Latest pass', a.Type,  a.ReceivedTime as 'Imported at'
FROM       Access AS a INNER JOIN
                      (SELECT     GateId, MAX(OpenTime) AS maxDate
                        FROM      Access
                        GROUP BY GateId) AS grp ON a.GateId = grp.GateId AND a.OpenTime = grp.maxDate INNER JOIN
                  Gate ON a.GateId = Gate.ID
                  order by Gate.ID

My Access table has around 2 mill records, but it has only 40 different GateId's. I want to select a line for every gate that will look like:
GateName        OpenTime        Type        Imported at
....................................................................................
Supergate        20/09/2013        1            21/09/2013
Ultragate          19/09/2013        0            22/09/2013

My Access class looks like this:

    public partial class Access : XPLiteObject
{
    Gate fGateId;
    [Association(@"AccessReferencesGate")]
    public Gate GateId
    {
        get { return fGateId; }
        set { SetPropertyValue<Gate>("GateId", ref fGateId, value); }
    }
    DateTime fOpenTime;
    public DateTime OpenTime
    {
        get { return fOpenTime; }
        set { SetPropertyValue<DateTime>("OpenTime", ref fOpenTime, value); }
    }
    byte fType;
    public byte Type
    {
        get { return fType; }
        set { SetPropertyValue<byte>("Type", ref fType, value); }
    }
    DateTime fReceivedTime;
    public DateTime ReceivedTime
    {
        get { return fReceivedTime; }
        set { SetPropertyValue<DateTime>("ReceivedTime", ref fReceivedTime, value); }
    }
    int fID;
    [Key(true)]
    public int ID
    {
        get { return fID; }
        set { SetPropertyValue<int>("ID", ref fID, value); }
    }
    public Access(Session session) : base(session) { }
}

My Gate class:

public partial class Gate : XPLiteObject
{
    int fID;
    [Key(true)]
    public int ID
    {
        get { return fID; }
        set { SetPropertyValue<int>("ID", ref fID, value); }
    }
    string fName;
    [Size(20)]
    public string Name
    {
        get { return fName; }
        set { SetPropertyValue<string>("Name", ref fName, value); }
    }
    }
    [Association(@"AccessReferencesGate", typeof(Access))]
    public XPCollection<Access> AccessCollection { get { return GetCollection<Access>("AccessCollection"); } }
    public Gate(Session session) : base(session) { }
}

Any answers, or even RTFM links will be appreciated!

Answer 1

Answer from DevExpress support center, that worked for me:

XPView view = new XPView(typeof(Access));
view.AddProperty("Name", "GateId.Name");
view.AddProperty("LatestPass", "[<Access>][GateId = ^.GateId].Max(OpenTime)");
view.AddProperty("Type", "Type");
view.AddProperty("ImportedAt", "ReceivedTime");
view.Criteria = CriteriaOperator.Parse("OpenTime = [<Access>][GateId = ^.GateId].Max(OpenTime)");

Answer 2

Something like

var accesses = new XPQuery<Access>(session);
var result = 
    from a in accesses 
    where a.OpenTime == a.GateId.AccessCollection.Max(b => b.OpenTime) 
    select new { a.GateId.Name, a.Type, a.ReceivedTime };