It seems that these features can’t be implements in the search time directly? I think these are very important features,do the graylog has the plan to have these features?
are there any other methods to implements such features instead?
Hey @quguilai,
if you need max and min values, use the statistics widget on the field you want to get the min/max from, that will call a aggregation endpoint of the Graylog API.
As far as I know actual aggregation logic inside the search query won’t be supported for a while, maybe a Graylog Dev can give a more elaborate answer. 
Hej @quguilai
currently the four mentioned functions are not available. We already have those in our github issues as feature request.
Some will be addressed in the next releases of Graylog but not within weeks.
You are always welcomed to build a plugin that gives that function to Graylog.
ok,get it
thanks so much