juniorLINQ
What is SelectMany in LINQ?
Updated May 16, 2026
Short answer
SelectMany flattens nested collections into one sequence.
Deep explanation
It projects each element into a collection and flattens results into a single sequence.
Real-world example
Getting all orders from all users.
Common mistakes
- Using Select instead of SelectMany causing nested lists.
Follow-up questions
- What is flattening?
- Where is SelectMany used?