The Average Session
Before StreamVerse can say whether a new player build helped, it needs a baseline: how long a typical sitting lasts today. The engagement team wants the mean length of a watch session across the whole log, to two decimal places, so next month's figure is comparable.
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 |
The table already exists in the database — there is nothing to create or load.
Task: Write a query that returns exactly one row with one column, avg_minutes, holding the mean of watch_minutes across every session, rounded to 2 decimal places.
Example output
If the typical sitting ran sixty-three and a half minutes, the single row would read — a figure needing only one decimal comes back as 63.5, not 63.50:
| avg_minutes |
|---|
| 63.5 |
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