# Write your MySQL query statement below
select salesperson.name from salesperson
where name not in
(select salesperson.name
from salesperson
left join orders on salesperson.sales_id = orders.sales_id
left join company on orders.com_id = company.com_id
where company.name = 'RED')
这种比较麻烦，子查询中联结了三个表，找出人员的名字，其实是没必要的，只需要联结两个表就可以了，找出人员的id在筛选即可。
# Write your MySQL query statement below
select name from salesperson where sales_id not in
(select orders.sales_id from orders left join company on orders.com_id = company.com_id
where company.name = 'RED')
这样会略微简单一点