How I solved LeetCode Challenge, Rank Scores!

Hi Everyone,

Today I will be reviewing how I solved LeetCode challenge, Rank Scores, using SQL.

Objective: 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       |
+-------+---------+

Important Note: For MySQL solutions, to escape reserved words used as column names, you can use an apostrophe before and after the keyword. For example `Rank`.

I solved this problem using Dense Rank. It’s similar to the Rank function. However, the Rank function can cause non-consecutive rankings if the tested values are the same.

I experienced this while trying to solve this challenge. Dense_Rank will always result in consecutive rankings.

It Passed!

Here is my final code:

select score,
 dense_rank() over (order by score desc) as rank
from scores;

Runtime: 448 ms, faster than 92.50% of Oracle online submissions for Rank Scores.

Memory Usage: 0B, less than 100.00% of Oracle online submissions for Rank Scores.