题解 | 获取每个部门中薪水最高的员工相关信息

SELECT dept_no, d.emp_no, salary
FROM dept_emp d
LEFT JOIN salaries s on d.emp_no=s.emp_no
WHERE (dept_no, salary) in 
(SELECT dept_no, max(salary)
FROM dept_emp d
LEFT JOIN salaries s on d.emp_no = s.emp_no
GROUP BY dept_no)
ORDER BY dept_no;