[amageed]

LINQ isn't SQL-specific and does apply generally. It can be used against the standard .NET framework objects and collections. There are different LINQ focuses or flavors, and there are 2 ways to write queries. There's LINQ to Objects, LINQ to XML, LINQ to SQL (no longer actively maintained; nowadays Entity Framework is the Microsoft alternative), and you can write your own LINQ providers to target other purposes.

As for syntax, there's the fluent syntax (chained methods), and there's the query syntax which is syntactic sugar that gets compiled to the methods. The query syntax is probably the biggest reason people mistake LINQ for being SQL specific since it resembles SQL.

E.g.,

  var results = SomeCollection.Where(c => c.SomeProperty < 10)
                              .Select(c => new { c.SomeProperty, c.OtherProperty });

The same thing in query syntax:

  var results = from c in SomeCollection
                where c.SomeProperty < 10
                select new { c.SomeProperty, c.OtherProperty };

Then you can iterate over both the same way:

  foreach (var result in results)
  {
      Console.WriteLine(result);
  }