JQL to select multiple projects in JIRA

[Garden16_]

I would like to create a multiple  custom picker in  JIRA and provide a JQL to  search and select  multiple project's that are in my JIRA instance. How do I get achieve it using JQL

[Nic Brough -Adaptavist-]

You will need to write an app to do that, or find one in the marketplace.   It's not something you can cobble together with a bit of JQL and a script.

I can't find anything that other people have written to do it, so it sounds like not a lot of people need it.  Could you tell us what problem it would solve for you?