Standard Query Operators
One of the core strengths of LINQ is the fact it unifies query operators across different data domains, ranging from in-memory objects to relational databases. To do so, it not only provides query syntax for mainstream languages like C# and Visual Basic but also establishes a set of commonly used query operators.
In this section, we take a look at all the standard query operators that ship with the .NET Framework, including some of their less commonly used, but useful, overloads. Keep in mind that some of those are exposed through language integrated query syntax, whereas others aren’t. For the latter set of operators, you can just use method invocation syntax to use them.