Friend requests ii who has the most friends

#
# Table: RequestAccepted
# +----------------+---------+
# | Column Name    | Type    |
# +----------------+---------+
# | requester_id   | int     |
# | accepter_id    | int     |
# | accept_date    | date    |
# +----------------+---------+
# (requester_id, accepter_id) is the primary key (combination of columns with unique values) for this table.
# This table contains the ID of the user who sent the request, the ID of the user who received the request, and the date when the request was accepted.
# Write a solution to find the people who have the most friends and the most friends number.
# The test cases are generated so that only one person has the most friends.
# The result format is in the following example.
# Example 1:
# Input:
# RequestAccepted table:
# +--------------+-------------+-------------+
# | requester_id | accepter_id | accept_date |
# +--------------+-------------+-------------+
# | 1            | 2           | 2016/06/03  |
# | 1            | 3           | 2016/06/08  |
# | 2            | 3           | 2016/06/08  |
# | 3            | 4           | 2016/06/09  |
# +--------------+-------------+-------------+
# Output:
# +----+-----+
# | id | num |
# +----+-----+
# | 3  | 3   |
# +----+-----+
# Explanation:
# The person with id 3 is a friend of people 1, 2, and 4, so he has three friends in total, which is the most number than any others.
# Follow up: In the real world, multiple people could have the same most number of friends. Could you find all these people in this case?
#

# Write your MySQL query statement below

SELECT id, COUNT(*) AS num
FROM (
  SELECT requester_id AS id FROM RequestAccepted
  UNION ALL
  SELECT accepter_id AS id FROM RequestAccepted
) t
GROUP BY id
ORDER BY num DESC
LIMIT 1;