How to calculate average salary per department?

Short answer: How to calculate average salary per department? var avgSalaryByDept = employees .GroupBy(e => e.Department) Follow : .Select(g => new { Department = g.Key, AverageSalary = g.Average(e => e.Salary) }); foreach (var dept in avgSalaryByDept) Console.WriteLine($"{dept.Department}: {dept.AverageSalary}"); How to calculate average salary per department?

Real-world example (ShopNest)

ShopNest uses LINQ to query orders: filter by date, project to a summary DTO, and order by total—readable C# that becomes SQL under EF Core.

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.