Leetcode 176. Second Highest Salary数据库

Write a SQL query to get the second highest salary from the Employeetable.

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

For example, given the above Employee table, the query should return 200 as the second highest salary. If there is no second highest salary, then the query should return null.

+---------------------+
| SecondHighestSalary |
+---------------------+
| 200                 |
+---------------------+

题目链接：https://leetcode.com/problems/second-highest-salary/

coalesce：返回表达式中第一个非空表达式

# Write your MySQL query statement below
select coalesce((select distinct salary from employee order by salary desc limit 1,1)) as SecondHighestSalary 

方法二：

# Write your MySQL query statement below
select (select distinct Salary from Employee order by Salary desc limit 1,1 )as SecondHighestSalary