How to group and order groups by count descending?

Short answer: How to group and order groups by count descending? var groupOrder = employees .GroupBy(e => e.Department) .OrderByDescending(g => g.Count()); foreach (var group in groupOrder) Console.WriteLine($"{group.Key} has {group.Count()} employees"); How to group and order groups by count descending?

Real-world example (ShopNest)

A sales report joins orders and customers, then GroupBy(c => c.City) to show revenue per city.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.