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

Not very efficient, but should work:

SELECT 
    CASE WHEN username LIKE 'GRP%' THEN username ELSE 'GRP_OTHERS' END AS username, 
    COUNT(*)
FROM host
WHERE seq BETWEEN 0 AND 2000
GROUP BY CASE WHEN username LIKE 'GRP%' THEN username ELSE 'GRP_OTHERS' END;