Friend Requests II: Who Has the Most Friends
Meta
Problem Statement
Meta needs to identify the most "social" users on the platform. In the request_accepted table, every row represents a friendship formed between requester_id and accepter_id.
Write an SQL query to find the person who has the most friends and the most friends count.
Rules:
- A person is a friend if they either requested the friendship or accepted it.
- The result should contain the id and the total number of friends (num).
- If there are multiple people with the same maximum number of friends, you only need to report one of them.
- Results must be sorted by num in descending order (implicit via LIMIT).
Tests your understanding of
Basic SQL, UNION ALL, Aggregation and LIMIT
Input Tables
request_accepted
| requester_id(INTEGER) | accepter_id(INTEGER) | accept_date(DATE) |
|---|---|---|
| 1 | 2 | 2016-06-01 |
| 1 | 3 | 2016-06-08 |
| 2 | 3 | 2016-06-08 |
| 3 | 4 | 2016-06-09 |
Expected Output
| id(INTEGER) | num(INTEGER) |
|---|---|
| 3 | 3 |
Tags
MediumBasic SQLUNION ALLAggregationLIMIT
15-20 min
58%