Find Followers Count
Twitter
Problem Statement
Data scientists at Twitter (X) need to identify the reach of different accounts. To do this, they require a simple tally of followers for every user on the platform.
Write an SQL query that will, for each user, return the number of followers.
Rules:
- Each row in the table represents a unique relationship where follower_id follows user_id.
- Return the result table containing user_id and followers_count.
- Results must be sorted by user_id in ascending order.
Tests your understanding of
Basic SQL, Aggregation, COUNT and Grouping
Input Tables
followers
| user_id(INTEGER) | follower_id(INTEGER) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 2 | 1 |
Expected Output
| user_id(INTEGER) | followers_count(INTEGER) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
Tags
EasyBasic SQLAggregationCOUNTGrouping
5-10 min
68%