sql notes: leetcode#177 nth highest salary

Problem

Write a SQL query to get the n^th highest salary from the Employee table.

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

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

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

Analysis

We can solve this problem with LIMIT and OFFSET. We can sort by salary in descending order first, then skip n-1 numbers and output the first number.

Solution

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CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
BEGIN
  SET N=N-1;
  RETURN (
      # Write your MySQL query statement below.
      SELECT DISTINCT Salary FROM Employee ORDER BY Salary DESC LIMIT 1 OFFSET N
  );
END

Link

177. Nth Highest Salary
(中文版) SQL 笔记: Leetcode#177 Nth Highest Salary