[LeetCode][SQL]Second Highest Salary
浏览数：29 /
时间：2015年06月12日
https://leetcode.com/problems/second-highest-salary/
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.
首先MySQL不支持top语法，要用limit代替。
select Salary from Employee order by Salary desc limit 1,1
这样写的话如果不存在，select出来是空，题目需要是null(掀桌。
Input: {"headers": {"Employee": ["Id", "Salary"]}, "rows": {"Employee": [[1, 100]]}}
Output: {"headers": ["Salary"], "values": []}
Expected: {"headers": ["SecondHighestSalary"], "values": [[null]]}
于是就需要在外面再包一层。为什么要加distinct呢，是因为不加过不了这个case：
+----+--------+ | Id | Salary | +----+--------+ | 1 | 100 | | 2 | 100 | +----+--------+
最终解法:
select (select distinct Salary from Employee order by Salary desc limit 1,1) as Salary;
郑重声明：本站内容如果来自互联网及其他传播媒体，其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享，并不代表本站赞同其观点和对其真实性负责，也不构成任何其他建议。
