Easy 🔗178. Rank Scores

📝문제 요약

Table: Scores

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| id          | int     |
| score       | decimal |
+-------------+---------+
id is the primary key (column with unique values) for this table.
Each row of this table contains the score of a game. Score is a floating point value with two decimal places.

Write a solution to find the rank of the scores. The ranking should be calculated according to the following rules:

• The scores should be ranked from the highest to the lowest.
• If there is a tie between two scores, both should have the same ranking.
• After a tie, the next ranking number should be the next consecutive integer value. In other words, there should be no holes between ranks.

Return the result table ordered by score in descending order.

The result format is in the following example.

Example 1:

Input:
Scores table:
+----+-------+
| id | score |
+----+-------+
| 1  | 3.50  |
| 2  | 3.65  |
| 3  | 4.00  |
| 4  | 3.85  |
| 5  | 4.00  |
| 6  | 3.65  |
+----+-------+
Output:
+-------+------+
| score | rank |
+-------+------+
| 4.00  | 1    |
| 4.00  | 1    |
| 3.85  | 2    |
| 3.65  | 3    |
| 3.65  | 3    |
| 3.50  | 4    |
+-------+------+

✏️문제 풀이

SELECT

SELECT score, DENSE_RANK() OVER (ORDER BY score DESC) as `rank`

• score : 점수
• rank : 등수
  • DENSE_RANK() 를 사용하여 동일한 값의 행에 동일한 순위를 부여하고 다음 순위를 건너뛰지 않고 연속적으로 부여
  • socre을 기준으로 내림차순 정렬
  • rank : 백틱으로 감싼이유는 rank가 예약어라서 충돌로 에러가 나는 것 같아서 이렇게 사용하였음

FROM

FROM Scores 

• 테이블면 Scores

💯제출 코드

SELECT score, DENSE_RANK() OVER (ORDER BY score DESC) as `rank`
FROM Scores