There are two extension methods for joining and grouping:
- Join: This method has four parameters: the sequence that you want to join with, the property or properties on the left sequence to match on, the property or properties on the right sequence to match on, and a projection
- GroupJoin: This method has the same parameters, but it combines the matches into a group object with a Key property for the matching value and an IEnumerable<T> type for the multiple matches
In the Main method, write the following statements:
// create two sequences that we want to join together
var categories = db.Categories.Select( c => new { c.CategoryID, c.CategoryName }).ToArray();
var products = db.Products.Select( p => new { p.ProductID, ...
