All problems

The Binge Leaderboard

mediumSQLJoinsGroupBy

Retention at StreamVerse works off one rule of thumb: people who watch a lot do not cancel. They want a leaderboard of who has spent the most time on the service. The awkward part is that the session log knows a number, not a person — the names live in a different table.

watch_events — one row per watch session: one sitting in which one subscriber watched one show. subscriber_id points at a row in subscribers, show_id at a row in shows, and watch_minutes is how long that sitting lasted. The same person can appear many times.

id subscriber_id show_id watch_minutes watch_date
1 1 1 45 2023-05-01
2 1 5 60 2023-05-03
3 2 3 20 2023-05-02
4 3 2 55 2023-05-05
5 4 1 40 2023-05-06
6 4 4 70 2023-05-08
7 1 3 25 2023-05-10
8 3 5 50 2023-05-11
9 2 2 30 2023-05-12
10 5 4 65 2023-05-14

subscribers — one row per person who pays for StreamVerse. plan is one of basic, standard or premium; country is a two-letter market code; signup_date is the day they signed up.

id name plan signup_date country
1 Ana Torres premium 2022-11-01 US
2 Ben Osei basic 2023-01-15 UK
3 Chloe Martin standard 2023-02-20 US
4 Dev Malhotra premium 2023-03-10 IN
5 Ella Novak basic 2023-04-05 UK

Both tables already exist in the database — there is nothing to create or load.

Task: Write a query that returns two columns, name and minutes, one row per subscriber who has at least one session, minutes being their total watch_minutes. Most minutes first; two subscribers on the same total come back in alphabetical order of name. A subscriber with no sessions at all does not appear.

Example output

Shape only — these subscribers and figures are invented:

name minutes
Femi Adeyemi 940
Hana Kito 780
Jonas Peak 615
Ingrid Sol 410
Lucia Braga 95

Sign in to solve this problem

Reading problems is free for everyone — solving them (Run, Submit, and tracking what you've solved) needs an account.

Sign in

Discussion

Sign in to join the discussion — reading is open to everyone.

Loading comments…