I have a multi person/ group column. I need to apply rest api filter on this column. I can filter it by values. eg:

```
_api/Web/Lists/getbytitle('testList')/items?$filter=(Access/Id+eq+21)

```

But when I apply the filter for null, it is not returning any rows.
 I tried :

```
_api/Web/Lists/getbytitle('testList')/items?$filter=(Access+eq+null)

```

This return no data.

I tried:

```
_api/Web/Lists/getbytitle('testList')/items?$filter=(Access/Id+eq+null)

```

This is throwing folllowing error:

```
<m:type>Microsoft.SharePoint.SPException</m:type>
<m:stacktrace>
at Microsoft.SharePoint.SPGlobal.HandleComException(COMException comEx) at Microsoft.SharePoint.Library.SPRequest.GetListItemDataWithCallback2(IListItemSqlClient pSqlClient, String bstrUrl, String bstrListName, String bstrViewName, String bstrViewXml, SAFEARRAYFLAGS fSafeArrayFlags, ISP2DSafeArrayWriter pSACallback, ISPDataCallback pPagingCallback, ISPDataCallback pPagingPrevCallback, ISPDataCallback pFilterLinkCallback, ISPDataCallback pSchemaCallback, ISPDataCallback pRowCountCallback, Boolean& pbMaximalView) at Microsoft.SharePoint.SPListItemCollection.EnsureListItemsData() at Microsoft.SharePoint.SPListItemEntityCollection.TryWriteAsOData(ODataWriter writer, RESTfulQuery query, ProxyContext proxyContext) at Microsoft.SharePoint.Client.ServerStub.Write(Object value, Uri path, ODataWriter writer, RESTfulQuery query, ProxyContext proxyContext) at Microsoft.SharePoint.Client.Rest.RestRequestProcessor.Process() at Microsoft.SharePoint.Client.Rest.RestRequestProcessor.ProcessRequest() at Microsoft.SharePoint.Client.Rest.RestService.ProcessQuery(Stream inputStream, IList`1 pendingDisposableContainer)
</m:stacktrace>

```