[SQL 문제 풀이] Find Followers Count (팔로워 수 찾기)

Can you solve this real interview question? Find Followers Count - Table: Followers +-------------+------+ | Column Name | Type | +-------------+------+ | user_id | int | | follower_id | int | +-------------+------+ (user_id, follower_id) is the primary key (combination of columns with unique values) for this table. This table contains the IDs of a user and a follower in a social media app where the follower follows the user.   Write a solution that will, for each user, return the number of followers. Return the result table ordered by user_id in ascending order. The result format is in the following example.   Example 1: Input: Followers table: +---------+-------------+ | user_id | follower_id | +---------+-------------+ | 0 | 1 | | 1 | 0 | | 2 | 0 | | 2 | 1 | +---------+-------------+ Output: +---------+----------------+ | user_id | followers_count| +---------+----------------+ | 0 | 1 | | 1 | 1 | | 2 | 2 | +---------+----------------+ Explanation: The followers of 0 are {1} The followers of 1 are {0} The followers of 2 are {0,1}