一、Rank Scores

Write a SQL query to rank scores. If there is a tie between two scores, both should have the same ranking. Note that after a tie, the next ranking number should be the next consecutive integer value. In other words, there should be no "holes" between ranks.

+----+-------+| Id | Score |+----+-------+| 1  | 3.50  || 2  | 3.65  || 3  | 4.00  || 4  | 3.85  || 5  | 4.00  || 6  | 3.65  |+----+-------+

For example, given the above Scores table, your query should generate the following report (order by highest score):+-------+------+

| Score | Rank |+-------+------+| 4.00  | 1    || 4.00  | 1    || 3.85  | 2    || 3.65  | 3    || 3.65  | 3    || 3.50  | 4    |+-------+------+ 分析：题意为 编写SQL对分数进行排序。如果两个分数相等，其排名应相同。注意在排名相等的分数之后，下一个排名的数值应该连续。换言之，排名之间不应该有“洞”（跳跃）。 思路：使用mysql的自定义变量。

# Write your MySQL query statement belowselect Score,Rank from (SELECT Score,       CASE           WHEN @dummy <=> Score THEN @Rank := @Rank            ELSE @Rank := @Rank +1    END AS Rank,@dummy := Score as dummyFROM  (SELECT @Rank := 0,@dummy := NULL) r,     ScoresORDER BY Score DESC) AS C

或者：

# Write your MySQL query statement belowSELECT Scores.Score, COUNT(Ranking.Score) AS RANK  FROM Scores     , (       SELECT DISTINCT Score         FROM Scores       ) Ranking WHERE Scores.Score <= Ranking.Score GROUP BY Scores.Id, Scores.Score ORDER BY Scores.Score DESC;