178-rank_scores.sql

-- 178. 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    |
-- +-------+------+


SELECT a.Score, COUNT(DISTINCT b.Score) as Rank
FROM Scores a JOIN Scores b ON a.Score <= b.Score
GROUP BY a.Id
ORDER BY a.Score DESC;