How to group by DESC order

Question

I have the following table called questions:

ID | asker 
1  | Bob
2  | Bob
3  | Marley

I want to select each asker only once and if there are

Answer 1

It's because ORDER BY is performed AFTER GROUP BY.

Try this:

SELECT * FROM questions
WHERE id IN 
(
    SELECT max(id) as id
    FROM questions 
    GROUP by asker 
    ORDER by id DESC
)