Leetcode]-176 第二高薪水

1、子查询

SELECT (SELECT DISTINCT Salary FROM Employee ORDER BY Salary DESC LIMIT 1 OFFSET 1) AS SecondHighestSalary;

2、ifnull和limit

SELECT IFNULL( (SELECT DISTINCT Salary FROM Employee ORDER BY Salary DESC LIMIT 1 OFFSET 1),NULL ) AS SecondHighestSalary;

3、max函数

`` SELECT MAX(Salary) FROM Employee WHERE Salary NOT IN (SELECT MAX(Salary) FROM Employee);

SELECT MAX(Salary) FROM EmployeeWhere Salary < (SELECT MAX(Salary) FROM Employee); ``