How to sum salaries of employees in a department?

Short answer: How to sum salaries of employees in a department? var totalSalaryHR = employees .Where(e => e.Department == "HR") .Sum(e => e.Salary); Console.WriteLine($"Total salary in HR: {totalSalaryHR}"); How to sum salaries of employees in a 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.