# $614. 二级关注者
# https://leetcode-cn.com/problems/second-degree-follower/

# SQL架构
Create table If Not Exists Follow (followee varchar(255), follower varchar(255));
Truncate table Follow;
insert into Follow (followee, follower) values ('Alice', 'Bob');
insert into Follow (followee, follower) values ('Bob', 'Cena');
insert into Follow (followee, follower) values ('Bob', 'Donald');
insert into Follow (followee, follower) values ('Donald', 'Edward');

# Write your MySQL query statement below
select
    followee as follower,
    count(follower) as num
from
    Follow
where
    followee in (
        select
            distinct follower
        from
            Follow
    )
group by
    followee
order by
    followee;

# clean-up
drop table Follow;