Graylog search with grouping and aggregation

I’m quite new to graylog and trying to find how to get statistics with aggregation. For example I have a field called ‘operation’ and another numeric field called ‘response_time’ . I’m trying to find the mean response time of all the distinct operation values. This is analogous to the count and groupby in SQL.
Can somebody help ?

currently that is not possible @libincheeran.

but we already have a feature issue for that: