Leetcode 176 Second Highest Salary

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

Employee

table.

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

For example, given the above Employee table, the second highest salary is

200

. If there is no second highest salary, then the query should return

null

.

如果值不存在，max()返回NULL

select max(Salary) from Employee
where Salary < (select max(Salary) from Employee)