题解 | #统计出当前各个title的员工对应的平均工资#
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
https://www.nowcoder.com/practice/c8652e9e5a354b879e2a244200f1eaae
SELECT t.title, AVG(s.salary) FROM salaries AS s LEFT OUTER JOIN titles AS t on s.emp_no = t.emp_no WHERE t.title IS NOT NULL GROUP BY t.title;
要注意有的员工可能没有职称,此时可以调换表联结的顺序,也可以先筛选再分组再聚合。