task: #177

Author: Ivanbyone

README.md

@@ -162,6 +162,7 @@ Useful for preparing for technical interviews and improving your SQL skills.
     - [3570. Find Books with No Available Copies](./leetcode/easy/3570.%20Find%20Books%20with%20No%20Available%20Copies.sql)
 2. [Medium](./leetcode/medium/)
     - [176. Second Highest Salary](./leetcode/medium/176.%20Second%20Highest%20Salary.sql)
+    - [177. Nth Highest Salary](./leetcode/medium/177.%20Nth%20Highest%20Salary.sql)
     - [180. Consecutive Numbers](./leetcode/medium/180.%20Consecutive%20Numbers.sql)
     - [184. Department Highest Salary](./leetcode/medium/184.%20Department%20Highest%20Salary.sql)
     - [550. Game Play Analysis IV](./leetcode/medium/550.%20Game%20Play%20Analysis%20IV.sql)

leetcode/medium/177. Nth Highest Salary.sql

@@ -0,0 +1,35 @@
+/*
+Question 177. Nth Highest Salary
+Link: https://leetcode.com/problems/nth-highest-salary/description/?envType=problem-list-v2&envId=database
+
+Table: Employee
+
++-------------+------+
+| Column Name | Type |
++-------------+------+
+| id          | int  |
+| salary      | int  |
++-------------+------+
+id is the primary key (column with unique values) for this table.
+Each row of this table contains information about the salary of an employee.
+ 
+
+Write a solution to find the nth highest distinct salary from the Employee table. If there are less than n distinct salaries, return null.
+*/
+
+CREATE OR REPLACE FUNCTION NTHHIGHESTSALARY(N INT) RETURNS TABLE (Salary INT) AS $$ --noqa: CP03 (function NthHighestSalary)
+BEGIN
+  IF N <= 0 THEN
+    Salary := NULL;
+    RETURN NEXT;
+    RETURN;
+  END IF;
+
+  RETURN QUERY (
+    SELECT DISTINCT e.salary
+    FROM Employee e
+    ORDER BY e.salary DESC
+    LIMIT 1 OFFSET (N - 1)
+  );
+END;
+$$ LANGUAGE plpgsql;