How to group by with a special condition

Question

Currently when I issue this SQL, it gets the distinct username.

I have some distinct usernames, which represent groups, e.g. GRP_BSN.

I would li

Answer 1

@bfavaretto is nice (+1 to him), but if you don't know about username prefix or they are different you can go with something like:

GROUP BY CASE
             WHEN REGEXP_LIKE(username, '^\d+$') THEN 'GRP_OTHERS'
                                                 ELSE username
         END