Unique Listeners per Artist

Return each artist and the number of distinct listeners, ordered by listeners descending then artist.

Table schema

Plays(id INT PRIMARY KEY, song VARCHAR(10), artist VARCHAR(10), user_id INT, play_date DATE)

Sample data

id | song | artist | user_id | play_date
1 | Sun | Aria | 1 | 2026-09-01
2 | Sun | Aria | 2 | 2026-09-01
3 | Moon | Aria | 1 | 2026-09-02
4 | Star | Bo | 3 | 2026-09-02
5 | Star | Bo | 1 | 2026-09-02
6 | Star | Bo | 2 | 2026-09-03
7 | Sun | Aria | 3 | 2026-09-03