题目描述

获取当前（to_date=’9999-01-01’）薪水第二多的员工的emp_no以及其对应的薪水salary

CREATE TABLE `salaries` (
`emp_no` int(11) NOT NULL,
`salary` int(11) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`from_date`));

输入描述

无

输出描述

emp_no	salary
10009	94409

题解

select emp_no, salary from salaries where to_date='9999-01-01' 
and salary=(select salary from salaries group by salary order by salary desc limit 1,1)
或
select emp_no, salary from salaries where to_date = '9999-01-01' 
and salary = (select distinct salary from salaries order by salary desc limit 1,1)

备注：

1. 需要注意多个人工资可能相同；
2. 筛选第二多的工资，可以用group by或distinct，但是前者效率要更高。