ADO SQL Query question

[cjmitton]

I have a very simple database that when someone does a search using my custom for it saves the following details to the database:
Username
Clientnumber
Date-time

On saving to the database the record gets a unique reference number.

The next time the access the list I want then to access the top 20 unique clientnumbers in the date/time order that they searched on them.

I've got it so that they pull back the top 20 unique record but struggling with getting them in Date order. My code is as follows:

Private Sub GetPrev()
Dim objMyConn As Object
Dim objMyCmd As Object
Dim objMyRecordset As Object
Dim Username As String
Username = Environ("UserName")
' Set the Variable with relevent code / data
Set objMyConn = New ADODB.Connection
Set objMyCmd = New ADODB.Command
Set objMyRecordset = New ADODB.Recordset
objMyConn.ConnectionString = "Driver=SQL Server;Server=SQL\SQL;Database=SQL;Trusted_Connection=Yes;"
objMyConn.Open
Set objMyCmd.ActiveConnection = objMyConn
    objMyCmd.CommandText = "Select top 20 cs_cltnum from CSResults group by cs_cltnum order by max(cs_DT) where cs_user like '" & Username & "'"
    objMyCmd.CommandType = adCmdText
    objMyCmd.Execute
Set objMyRecordset.ActiveConnection = objMyConn
    objMyRecordset.Open objMyCmd
objMyRecordset.MoveFirst
objMyRecordset.Sort "cs_DT Desc"
With Me.cmbcltnum
        .Clear
        Do
            .AddItem objMyRecordset!cs_cltnum
            objMyRecordset.MoveNext
        Loop Until objMyRecordset.EOF
End With
objMyRecordset.Close
objMyConn.Close
Set objMyConn = Nothing
Set objMyCmd = Nothing
Set objMyRecordset = Nothing
End Sub

I know that the SQL statment is messed up at the moment as I've been trying lots of different statements from when I was looking on google. any thoughts please?