Windows搜索C++（MFC）OLE DB或ADO组搜索

我必须运行如下组查询： 在System.ItemName上分组，然后从SystemIndex中选择前20名System.ItemName 但是当我使用C++ ADO记录集运行时，当我从Stand索引查询中选择Stop 20系统。 所以如何执行这样的组搜索

ADO代码：

_ConnectionPtr connection = NULL;
    hr = connection.CreateInstance(__uuidof(Connection));
_RecordsetPtr recordset = NULL;
hr = recordset.CreateInstance(__uuidof(Recordset));
hr = recordset->Open("GROUP ON System.Kind AGGREGATE COUNT() as 'Total' OVER ( SELECT TOP 20 System.ItemName, System.ItemUrl FROM SystemIndex )", 
    connection.GetInterfacePtr(), adOpenForwardOnly, adLockReadOnly, adCmdText);

经过长时间的尝试，我决定直接运行OLEDB，但检索搜索数据似乎很困难

OLE DB代码：

CDATA来源CDATA来源； hr=CDATA源代码。OpenFromInitializationStringconnectionstring

if (SUCCEEDED(hr))
{
    CSession cSession;
    if (SUCCEEDED(hr))
    {
        CCommand<CDynamicAccessor, CRowset> cCommand;
        hr = cCommand.Open(cSession, L"GROUP ON System.ItemName OVER ( SELECT TOP 20 System.ItemName, System.Itemurl FROM SystemIndex )");

        if (SUCCEEDED(hr))
        {

            for (hr = cCommand.MoveFirst(); S_OK == hr; hr = cCommand.MoveNext())
            {
                DBORDINAL columns= cCommand.GetColumnCount();
                for (DBORDINAL i = 1; i <= columns; i++)
                {
                    PCWSTR pszName = cCommand.GetColumnName(i);
                    //HOW TO GET DATA TO A sdt::string ?
                }
            }
            cCommand.Close();
        }
    }
}