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Counting the No-Shows

easySQLFilteringAggregation

Cancellations are the number the UrbanHop ops team watches most closely, because they move before anything else does. When drivers start going offline in a city, riders' bookings begin failing days before the revenue chart notices. So the daily standup opens with one figure: how many bookings ended up cancelled.

Both outcomes are recorded in the same column of the same table, which is what makes this the mirror image of the trips figure rather than a new kind of question.

rides — one row per booking. rider_id points at a row in riders and driver_id at a row in drivers. distance_km is the trip length in kilometres and fare the price in dollars; both are recorded when the booking is made, so a booking that never happened still carries them. status is either completed or cancelled. ride_date is the day the ride was booked for.

id rider_id driver_id distance_km fare ride_date status
1 1 1 5.2 12.5 2023-06-01 completed
2 1 4 3.0 8.0 2023-06-03 completed
3 2 2 10.0 22.0 2023-06-02 completed
4 3 1 2.1 6.5 2023-06-05 cancelled
5 3 4 4.4 11.0 2023-06-06 completed
6 4 3 7.8 18.0 2023-06-04 completed
7 5 2 1.5 5.0 2023-06-07 cancelled
8 2 2 12.3 26.5 2023-06-10 completed
9 1 1 6.6 15.0 2023-06-12 completed
10 4 3 3.3 9.0 2023-06-15 completed
11 5 2 8.8 19.5 2023-06-18 completed
12 3 4 2.9 7.5 2023-06-20 cancelled

The table already exists in the database — there is nothing to create or load.

Task: Write a query that returns one row with one column, cancelled_rides, holding how many bookings have a status of cancelled.

Example output

If seventeen bookings had fallen through, the single row would read:

cancelled_rides
17

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