Select latest record on many to many relationship - sql

Question

I have a many to many relationship like below. A user can change their role, and I want to get all users with their last role equals to role2 (example).
users
user_id | user_name | user_password
1 | user1 | *hashed password*
2 | user2 | *hashed password*
3 | user3 | *hashed password*
roles
role_id | role_name | role_description
1 | role1 | *description*
2 | role2 | *description*
user_roles
user_roles_id | user_id | role_id | created_at
1 | 1 | 1 | 2018-04-10 01:01:01
2 | 2 | 2 | 2018-04-10 01:01:02
3 | 3 | 1 | 2018-04-10 01:01:03
4 | 1 | 2 | 2018-04-12 01:01:01
5 | 1 | 1 | 2018-04-13 01:01:02
6 | 2 | 1 | 2018-04-14 01:01:01
7 | 3 | 2 | 2018-04-14 01:01:02
8 | 2 | 2 | 2018-04-15 01:01:01
9 | 1 | 2 | 2018-04-15 01:01:02
10 | 1 | 1 | 2018-04-16 01:01:01
From those tables, I want to get things like
user_id | role_id
2 | 2
3 | 2
But all this time I got
user_id | role_id
1 | 2
2 | 2
3 | 2
user1 should not be there because its last role was role1.
So what I'm trying to do is, get users where last role = 2.
Any help would be appreciated! Thanks in advance!
Addition
The results that I wanted is all data from users table. So it might be like
user_id | user_name | <and all of the rest>
2 | user2 | ...
3 | user3 | ...
So that, the field role_id I mentioned above is just reference to select the user.

Answer 1

This is one solution. Essentially, you are looking at each user's latest role, and only include it in the output, if the role is 2.
SELECT
ur.user_id, ur.role_id
FROM
user_roles ur
WHERE
ur.created_at = (SELECT MAX(created_at)
FROM user_roles
WHERE user_id = ur.user_id)
AND ur.role_id = 2
GROUP BY
ur.user_id, ur.role_id;
EDIT
Based on the additional information from the comments, the following will return all information from the Users table:
SELECT
u.*
FROM
users u INNER JOIN (
SELECT
ur.user_id
FROM
user_roles ur
WHERE
ur.created_at = (SELECT MAX(created_at)
FROM user_roles
WHERE user_id = ur.user_id)
AND ur.role_id = 2
GROUP BY
ur.user_id, ur.role_id) tmp ON tmp.user_id = u.user_id;

Answer 2

Use subquery with correlation approach and do the joins
select u.user_id, u.user_name, u.user_password,
r.role_id, r.role_name, r.role_description
from (select t.user_id, (select role_id from user_roles
where user_id = t.user_id
order by created_at desc LIMIT 1) as role_id
from user_roles t
group by t.user_id) tt
inner join users u on u.user_id = tt.user_id
inner join roles r on r.role_id = tt.role_id
where r.role_id <> 1;