Kas saaksite loetleda ja selgitada LINQ-s kasutatavate peamiste päringutüüpide?

The main types of queries in LINQ can be divided into two categories: data selection queries and data transformation queries.

1. Selection operators:

   • Where — filtering elements based on a condition.
   • Select — projection, transforming elements.
   • OrderBy / OrderByDescending — sorting.
   • GroupBy — grouping elements by key.

2. Aggregation operators:

   • Count — counting elements.
   • Sum, Average, Min, Max — calculating aggregate values.

3. Join operators:

   • Join — joining two sequences by key.
   • GroupJoin — grouping with join.

4. Elementary access operators:

   • First, FirstOrDefault, Single, SingleOrDefault — getting the first or only element.

5. Transformation operators:

   • Distinct — removing duplicates.
   • Skip, Take — skipping and selecting a certain number of elements.

Example:

var result = people
    .Where(p => p.Age > 18)         // filtering
    .OrderBy(p => p.Name)           // sorting
    .Select(p => p.Name);           // projection

Thus, LINQ provides a convenient and expressive syntax for working with collections and data.