题解 | #统计出当前各个title类型对应的员工当前薪水对应的平均工资#
统计出当前各个title类型对应的员工当前薪水对应的平均工资
http://www.nowcoder.com/practice/c8652e9e5a354b879e2a244200f1eaae
select title , avg(s.salary)
from
(select title ,
(select salary from salaries s where s.emp_no = t.emp_no) salary
from titles t) s
group by title
）