题目:
查找所有员工入职时候的薪水情况,给出emp_no以及salary, 并按照emp_no进行逆序(请注意,一个员工可能有多次涨薪的情况)
CREATE TABLE `employees` (
`emp_no` int(11) NOT NULL,
`birth_date` date NOT NULL,
`first_name` varchar(14) NOT NULL,
`last_name` varchar(16) NOT NULL,
`gender` char(1) NOT NULL,
`hire_date` date NOT NULL,
PRIMARY KEY (`emp_no`));
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`));
解答
- 我的答案
select distinct e.emp_no,s.salary
from employees e left join salaries s on e.emp_no = s.emp_no and e.hire_date = s.from_date
order by e.emp_no desc
注意:连接查询on
后面多个条件的时候,用and
连接,不是 ,
- 解答
链接:https://www.nowcoder.com/questionTerminal/23142e7a23e4480781a3b978b5e0f33a?answerType=1&f=discussion
来源:牛客网
方法一:获取salaries中from_data中最小的对应的salary和emp_no,因为salaries可能涨薪,所以这张表一个员工可能有多条记录。
SELECT
emp_no,
salary
FROM
salaries
GROUP BY
emp_no
HAVING
min( from_date )
ORDER BY
emp_no DESC
方法二:hire_data时间和from_data时间一致
SELECT
e.emp_no,
s.salary
FROM
employees AS e
INNER JOIN salaries AS s ON e.emp_no = s.emp_no
AND e.hire_date = s.from_date
ORDER BY
e.emp_no DESC
方法三:hire_data时间和from_data时间一致
SELECT
e.emp_no,
s.salary
FROM
employees AS e,
salaries AS s
WHERE
e.emp_no = s.emp_no
AND e.hire_date = s.from_date
ORDER BY
e.emp_no DESC