[LeetCode MySQL] 177. Nth Highest Salary

177. Nth Highest Salary

Write a SQL query to get the nth highest salary from the Employee table.

+----+--------+
| Id | Salary |
+----+--------+
| 1  | 100    |
| 2  | 200    |
| 3  | 300    |
+----+--------+

For example, given the above Employee table, the nth highest salary where n = 2 is 200. If there is no nth highest salary, then the query should return null.

+------------------------+
| getNthHighestSalary(2) |
+------------------------+
| 200                    |
+------------------------+

 

Solution

CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
BEGIN
  RETURN (
      select distinct if(ranks is null, null, salary)
      from (select dense_rank() over (order by salary desc) ranks, salary
      from employee) result
      where ranks = N
      
  );
END

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Reference: LeetCode 177. Nth Highest Salary