Can you elaborate on what you are trying to accomplish? Using stats you will lose all the other fields and you can't run another search after that with a starttime and endtime at the end. Have you tried eventstats?
I have events that have a start and an end. I would like to know how many events I have each second. so by computing before the report window an can count starts that have not ended yet, ie that are still running during my report window. I am using streamstats to count, I was not able to get meaningful data from eventstats.