Hi Janine,
What is the error message that you're getting? The following works for me on 8.1.6:
select
'Revision ' || content_revision.get_number(r.revision_id) || ' of ' ||
(select count(*) from cr_revisions where item_id = r.item_id)
|| ' for item: ' || content_item.get_title(r.item_id) as text
from cr_revisions r
where revision_id = 982;