How can I add sub tasks to a quick filter on a kanban board?

[Giovanna Luisi]

Apologies if this is super easy for most, but I am unable to make this work. 

I was asked for help on a board I am unfamiliar with. With the main board, the subtasks show currently.

This is the main board search query: 
(project = "XYZ" OR project = Ecosystem) AND labels = LabelWeAreUsing

The quick filter in question searches for the epic link, which is only enabled for the stories:
"Epic Link" =XYZproject-6878

How to modify the search query to make sure that what is returned by the quick filter includes the sub tasks? 

[Giovanna Luisi · Accepted solution]

Actually we managed, I believe with the off the shelf solution! This is the quick filter query that did it. 

"Epic Link"=NEWE-6878 OR issueFunction in subtasksOf("\"Epic Link\"=NEWE-6878")

[fad fozi]

Thanks bro! this is definitely what I am searching for!

[Nic Brough -Adaptavist-]

I am sorry, but you can't make this work off-the-shelf.

Sub-tasks are assumed to take the Epic Link of their parent (that makes perfect sense, they should).  But Atlassian have not coded for that, and sub-tasks do not appear to have epic links.

The solutions I've seen coded for in the past are to have a scripted "Epic Link everywhere" field, or to write a JQL function that understands to include sub-tasks.  But you'll need a scripting or automation app to do either of those.