题目描述

查找薪水变动超过15次的员工号emp_no以及其对应的变动次数t

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	t
10001	17
10004	16
10009	18

题解

select emp_no, count(*) as t from salaries group by emp_no having t>15;

拓展：

查找涨薪超过15的员工号emp_no以及其对应的变动次数

select a.emp_no,count(*) t from salaries a inner join salaries b
on a.emp_no=b.emp_no and a.to_date = b.from_date
where a.salary < b.salary
group by a.emp_no
having t>15