题解 | 对多个条件分组聚合在order by后用','隔开
汇总各个部门当前员工的title类型的分配数目
https://www.nowcoder.com/practice/4bcb6a7d3e39423291d2f7bdbbff87f8
select
de.dept_no,
dp.dept_name dept_name,
tl.title title,
count(tl.title) count
from
dept_emp de
join titles tl on de.emp_no = tl.emp_no
left join departments dp on de.dept_no = dp.dept_no
where
de.to_date = '9999-01-01'
group by
de.dept_no,
tl.title
order by
de.dept_no,
tl.title