牛客SQL題解 - 獲取所有部門中當前員工薪水最高的相關信息

題目描述

獲取所有部門中當前員工薪水最高的相關信息，給出dept_no, emp_no以及其對應的salary
CREATE TABLE `dept_emp` (
`emp_no` int(11) NOT NULL,
`dept_no` char(4) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`dept_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`));

輸出描述

dept_no	emp_no	salary
d001	10001	88958
d002	10006	43311
d003	10005	94692
d004	10004	74057
d005	10007	88070
d006	10009	95409

試題詳解

先建立子查詢篩選出當前最高薪水的員工，之後再從原始僱員表中取出相應僱員信息。代碼如下：

SELECT de.dept_no,de.emp_no,s.salary
FROM dept_emp AS de INNER JOIN salaries AS s
ON de.emp_no = s.emp_no
AND de.to_date = '9999-01-01'
AND s.to_date = '9999-01-01'
where s.salary = (select max(s2.salary)
              from dept_emp AS de2 inner join salaries AS s2
              on de2.emp_no = s2.emp_no
              and de2.to_date = '9999-01-01'
              and s2.to_date = '9999-01-01'
              where de2.dept_no = de.dept_no
              group by de2.dept_no)
order by de.dept_no;