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

使用左连接left join 和求平均值函数avg
select t.title as title,avg(s.salary) as avg from titles as t
left join salaries as s on s.emp_no = t.emp_no
GROUP BY t.title
HAVING avg(s.salary)