How to check date values between vb.net and sql

Dim table As New DataTable()
Dim query As String = "select Billno,Billdate,PName,Qty,TName from CancelOrder where @Billdate1 >= @Billdate2"

Using cn As New SqlConnection(Configuration.DefaultConnectionString)
    Using cmd As New SqlCommand(query.ToString(), cn)
        cmd.Parameters.Add("@Billdate1", SqlDbType.DateTime).Value = Billdate1
        cmd.Parameters.Add("@Billdate2", SqlDbType.DateTime).Value = Billdate2

        cn.Open()

        Using reader As SqlDataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection)
            table.Load(reader)
        End Using
    End Using
End Using