关于mysql的查询问题，子查询

这是我的查询语句：

SELECT

• FROM departments WHERE department_id = (SELECT department_id FROM employees GROUP BY department_id HAVING AVG(salary) = (SELECT MIN(AVG(salary)) FROM employees GROUP BY department_id))

最后执行的时候，mysql报出了
错误代码： 1111 Invalid use of group function

求大神指点，该怎么改这个sql语句？