MySQL select result row numbers - mysql

Question

I have a table which contains users and some scores associated with them. something like this:
uid | username | score | time_spent
1 | test | 25 | 12
then I am sorting this table based on score and time_spent. As a result I get some kind of highscores table.
what I want to do is to assign row numbers to this sorted table to have the information about the specific users place in the highscores table and then select a specific user from this sorted table with row number.
I tried to do it like this:
SET #row_number = 0;
SELECT * FROM
(SELECT uid, username, score, time_spent, #row_number:=#row_number+1 AS row_number,
SUM(score) AS points_awarded,
MIN(time_spent) AS time
FROM results
GROUP BY uid
ORDER BY points_awarded DESC, time ASC) as t
WHERE t.uid=1
but this does not work correctly. The result row I get has always the last number of total records.

Answer 1

You must have the #row_number in the outer query:
SET #row_number = 0;
SELECT
t.*, #row_number:=#row_number+1 AS row_number
FROM (
SELECT
uid, username,
SUM(score) AS points_awarded,
MIN(time_spent) AS time
FROM results
GROUP BY uid, username
) t
ORDER BY t.points_awarded DESC, t.time ASC
See the demo.
INSERT INTO results
(`uid`, `username`, `score`, `time_spent`)
VALUES
('1', 'test1', '25', '12'),
('1', 'test1', '20', '13'),
('1', 'test1', '20', '11'),
('2', 'test2', '12', '17'),
('2', 'test2', '29', '16'),
('2', 'test2', '25', '15'),
('3', 'test3', '45', '18'),
('3', 'test3', '15', '69');
Results:
| uid | username | points_awarded | time | row_number |
| --- | -------- | -------------- | ---- | ---------- |
| 2 | test2 | 66 | 15 | 1 |
| 1 | test1 | 65 | 11 | 2 |
| 3 | test3 | 60 | 18 | 3 |

Answer 2

If you only want the position of a single user at a time, the following should work:
-- get best score and time for the user
SELECT score, time_spent
INTO #u_score, #u_time
FROM results
WHERE uid = 2
ORDER BY score DESC, time_spent ASC
LIMIT 1;
SELECT *, -- below: count "better" distinct users
(SELECT COUNT(DISTINCT uid)+1 FROM results WHERE score > #u_score
OR (score = #u_score AND time_spent < #u_time)) AS pos
FROM results
WHERE uid = 2
AND score = #u_score
AND time_spent = #u_time;
EDIT: The request below should give you the complete "leaderboard", which you can then use as subquery from to get a specific user, like you did in your example:
SET #row_number = 0;
SELECT t.*, #row_number:=#row_number+1 AS row_number
FROM (
SELECT r1.*
FROM results r1
LEFT JOIN results r2
ON r1.uid = r2.uid
AND (r1.score < r2.score
OR (r1.score = r2.score
AND r1.time_spent > r2.time_spent))
WHERE r2.uid IS NULL
ORDER BY r1.score DESC, r1.time_spent ASC
) AS t
EDIT2: I assumed each row in your table was a separate score "attempt" and that you wanted to take into consideration the best attempt of each user, but it looks like you want the sum of these scores, so forpas's answer is the one you want :)