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.
# Write your MySQL query statement belowSELECT max(Salary) FROM Employee WHERE Salary < (SELECT max(Salary) FROM Employee)
题目解析：
SELECT max(Salary) FROM Employee WHERE Salary < (SELECT max(Salary) FROM Employee)
Using max() will return a NULL if the value doesn't exist. So there is no need to UNION a NULL. Of course, if the second highest value is guaranteed to exist, using LIMIT 1,1 will be the best answer.