LeetCode-MySQL基础题之176(第二高的薪水)

Created 5 years ago by 高永立, Updated 5 years ago Revision #1 2481 views 2 likes 0 collects

编写一个 SQL 查询，获取 Employee 表中第二高的薪水（Salary）。

Id	Salary
1	100
2	200
3	300

例如上述 Employee 表，SQL查询应该返回 200 作为第二高的薪水。如果不存在第二高的薪水，那么查询应返回 null。

SecondHighestSalary
200

对应的SQL查询语句如下：

IFNULL(field,Default) as alias 的使用方法

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

SELECT DISTINCT Salary AS SecondHighestSalary
FROM Employee
ORDER BY Salary DESC
LIMIT 1, 1