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Question
Formatted question description: https://leetcode.ca/all/177.html
Table: Employee
+-------------+------+ | Column Name | Type | +-------------+------+ | id | int | | salary | int | +-------------+------+ id is the primary key column for this table. Each row of this table contains information about the salary of an employee.
Write an SQL query to report the nth
highest salary from the Employee
table. If there is no nth
highest salary, the query should report null
.
The query result format is in the following example.
Example 1:
Input: Employee table: +----+--------+ | id | salary | +----+--------+ | 1 | 100 | | 2 | 200 | | 3 | 300 | +----+--------+ n = 2 Output: +------------------------+ | getNthHighestSalary(2) | +------------------------+ | 200 | +------------------------+
Example 2:
Input: Employee table: +----+--------+ | id | salary | +----+--------+ | 1 | 100 | +----+--------+ n = 2 Output: +------------------------+ | getNthHighestSalary(2) | +------------------------+ | null | +------------------------+
Algorithm
Change the 1 after OFFSET
to N-1
, but then MySQL will report an error and it is estimated that the operation is not supported. Then we can add a SET N = N-1
in front.
Code
SQL
CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
BEGIN
DECLARE M INT;
SET M=N-1; # index issue
RETURN (
# Write your MySQL query statement below.
SELECT DISTINCT Salary
FROM Employee
ORDER BY Salary DESC
LIMIT 1
OFFSET M
);
END