Find duplicate departments .GroupBy(e => e.Department) .Where(g => g.Count() > 1)?

Short answer: var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key);

Example code

var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key); var duplicateDepts = employees .Select(g => g.Key);

Real-world example (ShopNest)

ShopNest filters active products with products.Where(p => p.IsActive && p.Stock > 0) before showing the catalog.

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.