update

Author: kamyu104

MySQL/rank-scores.sql

@@ -0,0 +1,45 @@
+# Time:  O(n^2)
+# Space: O(n)
+#
+# 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    |
+#    +-------+------+
+#
+
+# Write your MySQL query statement below
+SELECT Ranks.Score, Ranks.Rank FROM Scores LEFT JOIN 
+       ( SELECT l.Score, @curRow := @curRow + 1  Rank 
+              FROM (SELECT DISTINCT(Score) FROM Scores ORDER by Score DESC) l 
+              JOIN (SELECT @curRow := 0) r
+       ) Ranks 
+       ON Scores.Score = Ranks.Score
+       ORDER by Score DESC
+
+
+# Time:  O(n^3)
+# Space: O(n)
+# Write your MySQL query statement below
+ SELECT Score,  (SELECT COUNT(DISTINCT(Score)) FROM  Scores b WHERE b.Score > a.Score) + 1 AS Rank
+       FROM Scores a
+       ORDER by Score DESC

README.md

@@ -715,12 +715,15 @@ Problem         |  Solution       |  Time           | Space           | Difficul
 --------------- | --------------- | --------------- | --------------- | -------------- | -----
 [Combine Two Tables] | [combine-two-tables.sql] | _O(m + n)_   | _O(m + n)_ | Easy     |
 [Nth Highest Salary] | [nth-highest-salary.sql] | _O(n^2)_   | _O(n)_ | Medium         |
+[Rank Scores] | [[rank-scores.sql] | _O(n^2)_       | _O(n)_          | Medium         |
 [Second Highest Salary] | [second-highest-salary.sql] | _O(n)_ | _O(1)_ | Easy         |
 
 [Combine Two Tables]:https://oj.leetcode.com/problems/combine-two-tables/
 [combine-two-tables.sql]:https://github.com/kamyu104/LeetCode/blob/master/MySQL/combine-two-tables.sql
 [Nth Highest Salary]:https://oj.leetcode.com/problems/nth-highest-salary/
 [nth-highest-salary.sql]:https://github.com/kamyu104/LeetCode/blob/master/MySQL/nth-highest-salary.sql
+[Rank Scores]:https://oj.leetcode.com/problems/rank-scores/
+[rank-scores.sql]:https://github.com/kamyu104/LeetCode/blob/master/MySQL/rank-scores.sql
 [Second Highest Salary]:https://oj.leetcode.com/problems/second-highest-salary/
 [second-highest-salary.sql]:https://github.com/kamyu104/LeetCode/blob/master/MySQL/second-highest-salary.sql