sql13（Leetcode570至少有5名直接下属的经理）

代码：

脑子记不住 语法全靠试..

# Write your MySQL query statement below
select b.name
from (
    select managerId,count(managerId) as num
    from Employee
    group by managerId
) a
left join Employee b
on a.managerId=b.id
where a.num>=5 and b.name is not NULL