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
不同类型用group by先分组，再用order by排序
select t.title,avg(s.salary) as average
from titles as t
join salaries as s
on t.emp_no = s.emp_no
group by t.title
order by average
