Peak Request Hour per City

SQL practice question · Hard · Date & Time · Ola

Pool all days together and group requests by city and hour of day (0-23, from requested_at). The peak hour of a city is the hour with the most requests; ties go to the hour with the higher share of status 'NO_DRIVER', and if still tied, to the earlier hour. Return city, peak_hour (integer), requests and no_driver_pct = 100 * NO_DRIVER requests / requests in that hour, ROUND to 1. Order by city.

Table: ride_requests

Schema of ride_requests
ColumnType
request_idINTEGER
cityTEXT
requested_atTIMESTAMP
statusTEXT
Sample rows of ride_requests
request_idcityrequested_atstatus
1Bengaluru2026-06-01 09:05:00COMPLETED
2Bengaluru2026-06-01 09:40:00NO_DRIVER
3Bengaluru2026-06-02 09:15:00COMPLETED
4Bengaluru2026-06-01 18:10:00CANCELLED
5Bengaluru2026-06-02 18:20:00COMPLETED
6Pune2026-06-01 08:00:00COMPLETED
7Pune2026-06-01 20:30:00NO_DRIVER
8Pune2026-06-02 20:45:00COMPLETED
Expected output on the sample data
citypeak_hourrequestsno_driver_pct
Bengaluru9333.3
Pune20250

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