学习mysql176. 第二高的薪水
Employee
表:
+-------------+------+ | Column Name | Type | +-------------+------+ | id | int | | salary | int | +-------------+------+ id 是这个表的主键。 表的每一行包含员工的工资信息。
编写一个 SQL 查询,获取并返回 Employee
表中第二高的薪水 。如果不存在第二高的薪水,查询应该返回 null
。
查询结果如下例所示。
示例 1:
输入: Employee 表: +----+--------+ | id | salary | +----+--------+ | 1 | 100 | | 2 | 200 | | 3 | 300 | +----+--------+ 输出: +---------------------+ | SecondHighestSalary | +---------------------+ | 200 | +---------------------+
示例 2:
输入: Employee 表: +----+--------+ | id | salary | +----+--------+ | 1 | 100 | +----+--------+ 输出: +---------------------+ | SecondHighestSalary | +---------------------+ | null | +---------------------+
select ifnull( (select distinct salary from Employee order by salary desc limit 1 offset 1) ,null) as SecondHighestSalary