For each department, show average salary?

Short answer: For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary = g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary =… g.Average(e => e.Salary) }); For… each department, show average salary var avgByDept =…

Explain a bit more

employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary = g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary =… g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary = g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary =… g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary = g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees…

Example code

For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary = g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary =… g.Average(e => e.Salary) }); For… each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary = g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary =… g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary = g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary =… g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary = g.Average(e => e.Salary) }); For each department, show average salary var avgByDept = employees .GroupBy(e => e.Department) .Select(g => new Department = g.Key, AverageSalary =… g.Average(e => e.Salary) });

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.