题解 | #查找employees表emp_no与last_name的员工信息#
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
简单的多表查询
select a.title ,avg(a.salary) from
(select a.emp_no,title,salary from titles a left join salaries b on a.emp_no=b.emp_no )a
group by a.title order by avg(a.salary)
