database - listagg data to useable format?

Question

This is my first time working with the LISTAGG function and I'm confused. I can select the data easily enough, but the characters of the USERS column all have spaces in between them, and when trying to copypaste it, no data from that column is copied. I've tried with two different IDEs. Am I doing something wrong?

Example:

select course_id, listagg(firstname, ', ') within group (order by course_id) as users
    from (
      select distinct u.firstname, u.lastname, u.student_id, cm.course_id
      from course_users cu
      join users u on u.pk1 = cu.users_pk1
      join course_main cm on cm.pk1 = cu.crsmain_pk1
      and cm.course_id like '2015SP%'
      )
group by course_id;

Yields:

Answer 1

I had similar problem, it turned out that the problem was with encoding. I got this solved like this (change to another encoding if needed):

...listagg(convert(firstname, 'UTF8', 'AL16UTF16'), ', ')...