it depends on what exactly you'd like to see in your query. If you only need to see the current value, that will be possible in building a query and using the criteria "Creation Date is within the previus 2 Month(s)" for example. But historical data is currently not possible out of the box.
For real historic data, SQL will come in handy. I've implemented something similar once. I'll try to describe, how I achieved it:
- Using the Console, I've created a new Object in the Incident Management, that contained all relevant data attributes I needed (e.g. ID, Ticket Creation Date, Ticket Creation User, etc.).
- Then I scripted a Stored Procedure, that runs on every 1st of a month and selects all Incidents with creation date last month and status equals open.
- The Stored Procedure then inserted these information in the new object or table so that these historical data can be queried.
- Finally I created the queries and fitted them into the dashboard as line graph or bar graph.
If you've got a license for Xtraction, it will look a lot better in there than in native Service Desk. But it will work anyways.
I hope it helps!