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题目:
https://leetcode-cn.com/problems/second-highest-salary/
题意:
思路:
用order by对薪水降序排序,用limit 1, 1拉出第二条,用IFNULL函数判断是否有第二条数据,没有输出NULL
代码:
# Write your MySQL query statement below
SELECT IFNULL(
(
SELECT DISTINCT Salary
FROM Employee
ORDER BY Salary DESC
LIMIT 1, 1
), NULL
) AS SecondHighestSalary