Subtring from url field and then group using the url

I have a field "BackendURL" which contains different url's. for eg : http://abc.com/emp?name=jim&no=101 http://abc.com/emp?name=tim&no=102 http://gef.com/vehicle I am trying to generate a report by grouping the url's. Now when i group i want to uniquely identify the backend url , but ignore the queury params (anything after ?). I wrote this rex command to create a new field to substring the value before ? , but it does not work when the url does not contain "?" . index="idx" Consumer|rex field=BackendURL "^(?.+?)\?"|stats count by BackendURL,url_noparams, host Thanks and regards Arun