How to write JQL to get issue start date

[Haran Rasalingam]

I want to measure average cycle times of issues from the date an issue is put in progress until it is resolved. Currently I am only able to easily measure this from date created to date resolved, but this does not give me the duration of work in progress on an issue.

[Nic Brough -Adaptavist-]

JQL is for finding issues, so that's not going to help you at all.

You need to find or write something that will extract the "in progress" start date and the resolved date from the issue history, and calculate the time between them for display.  I'd do it with a scripted field from the Script runner, but there are other options (other scripting add-ons, reporting, etc)