Question
Formatted question description: https://leetcode.ca/all/178.html
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 |
+-------+------+
Algorithm
For each score, find out how many different scores are greater than or equal to the score in the table, and then sort them in descending order.
Or, Join (is the short form of Inner Join), the condition is that the score of the right table is greater than or equal to the left table, and then the groups are ranked in descending order of the scores.
Code
SQL
SELECT Score,
(SELECT COUNT(DISTINCT Score) FROM Scores WHERE Score >= s.Score) AS Rank
FROM Scores s ORDER BY Score DESC;
--
SELECT s.Score, COUNT(DISTINCT t.Score) Rank
FROM Scores s JOIN Scores t ON s.Score <= t.Score
GROUP BY s.Id ORDER BY s.Score DESC;