SQL获取第2大值的记录:获取第二高薪水(MySQL)
程序员文章站
2022-03-04 23:34:28
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。+---------------------+| SecondH......
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 |
+---------------------+
代码1:
# Write your MySQL query statement below
select (select Salary from Employee where Salary < (select Salary from Employee order by Salary DESC limit 1) order by Salary DESC limit 1) as SecondHighestSalary
代码2:
# Write your MySQL query statement below
select (select distinct Salary from Employee order by Salary DESC limit 1,1) as SecondHighestSalary
# select (select distinct Salary from Employee order by Salary DESC limit 1 offset 1) as SecondHighestSalary
代码3:
# Write your MySQL query statement below
select ifnull((select distinct Salary from Employee order by Salary DESC limit 1,1), NULL) as SecondHighestSalary
# select ifnull((select distinct Salary from Employee order by Salary DESC limit 1 offset 1), NULL) as SecondHighestSalary
笔记:
代码3是常见模板。不过,似乎IFNULL(([SQL Query Set]), NULL)是多余的。就目前看来,更像是“画蛇添足”:一个 SQL Query Set 只有 非NULL 和 NULL 两种情况。
本文地址:https://blog.csdn.net/qq_21264377/article/details/107924737