1729. Find Followers Count
Description
Table: Followers
+-------------+------+ | Column Name | Type | +-------------+------+ | user_id | int | | follower_id | int | +-------------+------+ (user_id, follower_id) is the primary key 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 an SQL query that will, for each user, return the number of followers.
Return the result table ordered by user_id.
The query 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}