Find Followers Count
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Medium
Find Followers Count
You have a Followers table where each row represents that a user (follower_id) follows another user (user_id). Write a SQL query to find the number of followers for each user. Return the result ordered by user_id ascending. (user_id, follower_id) is the primary key.
Examples
Example 1
User 0 is followed by user 1. User 1 is followed by user 0. User 2 is followed by users 0 and 1.
Approach hint
Start with a simple approach, explain the trade-off, then move toward a cleaner or more scalable solution.
Common mistake
Skipping assumptions, edge cases, or trade-offs can make an otherwise good answer feel incomplete.
query.sql