using (var context = new ProductShopDbContext())
            {
                var selection = context.Categories
                                       .OrderBy(c => c.Name)
                                       .Select(c => new
                                       {
                                           c.Name,
                                           ProductsCount = c.CategoryProducts.Count(),
                                           AvgPrice = c.CategoryProducts.Select(cp => cp.Product.Price).Average(),
                                           TotalIncome = c.CategoryProducts
                                                          .Where(cp => cp.Product.BuyerId != null)
                                                          .Select(cp => cp.Product.Price).Sum()
                                       })
                                       .ToArray();
            }