LeetCode176. Second Highest Salary
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 second highest salary from the Employee
table. If there is no second highest salary, the query should report null
.The query result format is in the following example.
Input: Employee table: +----+--------+ | id | salary | +----+--------+ | 1 | 100 | | 2 | 200 | | 3 | 300 | +----+--------+ Output: +---------------------+ | SecondHighestSalary | +---------------------+ | 200 | +---------------------+
select salary as SecondHighestSalary from (
select salary, RANK () OVER (ORDER BY salary DESC) RANK from Employee
) where RANK=2
select MAX(salary) "SecondHighestSalary" from employee
where salary < (select max(salary) from employee);
WITH real_query AS (
select salary as SecondHighestSalary from (
select salary, dense_rank() OVER (ORDER BY salary DESC) RANK from Employee
) where RANK=2
)
SELECT SecondHighestSalary FROM real_query
union
select null FROM dual
WHERE NOT EXISTS(SELECT 1 FROM real_query);
https://marketing.ares.com.tw/newsletter/2015-01/oracle
https://blogs.ontoorsolutions.com/post/3_ways_to_find_sec_highest_salary/
https://www.techonthenet.com/oracle/questions/second_highest.php
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