176. Second Highest Salary

LeetCode SQL 50 Solution/176. Second Highest Salary.SQL

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+176. Second Highest Salary
+Solved
+Medium
+Topics
+Companies
+SQL Schema
+Pandas Schema
+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 second highest distinct salary from the Employee table. If there is no second highest salary, return null (return None in Pandas).
+
+The result format is in the following example.
+
+
+
+Example 1:
+
+Input: 
+Employee table:
++----+--------+
+| id | salary |
++----+--------+
+| 1  | 100    |
+| 2  | 200    |
+| 3  | 300    |
++----+--------+
+Output: 
++---------------------+
+| SecondHighestSalary |
++---------------------+
+| 200                 |
++---------------------+
+Example 2:
+
+Input: 
+Employee table:
++----+--------+
+| id | salary |
++----+--------+
+| 1  | 100    |
++----+--------+
+Output: 
++---------------------+
+| SecondHighestSalary |
++---------------------+
+| null                |
++---------------------+ 
+
+WITH
+  RankedEmployees AS (
+    SELECT *, DENSE_RANK() OVER(ORDER BY salary DESC) AS `rank`
+    FROM Employee
+  )
+SELECT MAX(salary) AS SecondHighestSalary
+FROM RankedEmployees
+WHERE `rank` = 2;