How do I return query results as a comma separated list in SQL?

[Laurie Huth]

Issue: I am using the Jira Issue/Filter macro in a Confluence page. In Jira, there is a list of items selected. I want to have commas or semi commas when I pull it into Confluence. 

For example, currently in Jira there is an External Document field:

Then the table cell in Confluence shows: (note, no commas or anything to separate the list)

Question: How do I enter commas or semicolons or something to separate each item?

Here is my SQL so far: 

FORMATWIKI(SUM("External: " + 'External Document')) AS 'Resources'