/* #先查询记录 select count(*) as 'sum' FROM salaries as s left join dept_emp as de on s.emp_no = de.emp_no WHERE dept_no is not NULL GROUP by dept_no */ select depart.dept_no, depart.dept_name, fir.s as 'sum' FROM departments as depart join (select dept_no, count(*) as s FROM salaries as s left join dep...