Driver Supply Map
Supply planning at UrbanHop starts with a headcount per city. A city with one driver has no slack at all — that driver takes a day off and the city effectively closes — so the shape of the distribution matters more to the planning team than the total.
The cities are not listed in a table of their own; they exist only as text written on each driver's row, so the report covers exactly the cities that have drivers in them. A city UrbanHop has launched in but has not recruited for yet is invisible here, which is itself worth knowing.
drivers — one row per driver on the platform. rating is their running star rating out of 5, and city is the city they drive in.
| id | name | city | rating |
|---|---|---|---|
| 1 | Sam Rios | Austin | 4.9 |
| 2 | Priya Desai | Denver | 4.6 |
| 3 | Oscar Lund | Seattle | 4.8 |
| 4 | Nina Cole | Austin | 4.2 |
The table already exists in the database — there is nothing to create or load.
Task: Write a query that returns one row per city, with city and how many drivers are registered there as n_drivers. Best-supplied city first; cities with the same number of drivers are separated alphabetically by city.
Example output
Shape only — these cities and headcounts are invented:
| city | n_drivers |
|---|---|
| Portland | 6 |
| Boise | 3 |
| Tulsa | 3 |
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