LeetCode-SQL-178. Score ranking

https://leetcode-cn.com/problems/rank-scores/

SELECT Score, Rank FROM
(SELECT Score,
@cur := IF(@preScore = Score, @cur+0,@cur:=@cur+1) AS Rank,
@preScore := Score
FROM Scores, (
SELECT @cur :=0, @preScore := null
) help
ORDER BY Score DESC) s