How to search for label across all projects using ScriptRunner

[Matt]

I'm trying to use:

issueFieldMatch (subquery, fieldname, regexp)

to search *all* projects for labels that include a particular string.  This works if I set the subquery parameter to something like "project = foo", but how do I search for the fieldname and regexp across all projects?

Thanks.  

[Fran Garcia]

You can use something like "project is not EMPTY" or any other subquery that returns every single issue.

Be careful with the performance