Is it possible to use group by without aggregate functions?

Question

SQL

I have never seen that group by was used without aggregate functions, in fact, a logical question arose: "is it possible at all?", if so, please give an example.

Answer 1

SELECT u.id, u.name, e.value FROM users u, emails e
      WHERE u.id=e.userid GROUP BY u.id, u.name

Here is a GROUP BY example without aggregate functions.
Naturally, only one lucky value will get as value from emails.

Answer 2

You can, of course, it just doesn’t make much sense, only together with subqueries, for example (select the last entry in a group, for example).