Except介绍

LINQ to SQL语句Union/Intersect/Except介绍2016-01-31
using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace BegVCSharp_23_15_SetOperators{class Customer{public string ID { get; set; }public string City { get; set; }public string Country { get; set; }public string Region { get; set; }public decimal Sales { get; set; }}class Order{public string ID { get; set; }public decimal Amount { get; set; }}class Program{static void Main（string[] args）{List<Order> orders = new List<Order> {new Order { ID="P", Amount=100 },new Order { ID="Q", Amount=200 },new Order { ID="R", Amount=300 },new Order { ID="S", Amount=400 },new Order { ID="T", Amount=500 },new Order { ID="U", Amount=600 },new Order { ID="V", Amount=700 },new Order { ID="W", Amount=800 },new Order { ID="X", Amount=900 },new Order { ID="Y", Amount=1000 },new Order { ID="Z", Amount=1100 }};List<Customer> customers = new List<Customer> {new Customer { ID="A", City="New York", Country="USA", Region="North America", Sales=9999},new Customer { ID="B", City="Mumbai", Country="India", Region="Asia", Sales=8888},new Customer { ID="C", City="Karachi", Country="Pakistan", Region="Asia", Sales=7777},new Customer { ID="D", City="Delhi", Country="India", Region="Asia", Sales=6666},new Customer { ID="E", City="So Paulo", Country="Brazil", Region="South America", Sales=5555 },new Customer { ID="F", City="Moscow", Country="Russia", Region="Europe", Sales=4444 },new Customer { ID="G", City="Seoul", Country="Korea", Region="Asia", Sales=3333 },new Customer { ID="H", City="Istanbul", Country="Turkey", Region="Asia", Sales=2222 },new Customer { ID="I", City="Shanghai", Country="China", Region="Asia", Sales=1111 },new Customer { ID="J", City="Lagos", Country="Nigeria", Region="Africa", Sales=1000 },new Customer { ID="K", City="Mexico City", Country="Mexico", Region="North America", Sales=2000 },new Customer { ID="L", City="Jakarta", Country="Indonesia", Region="Asia", Sales=3000 },new Customer { ID="M", City="Tokyo", Country="Japan", Region="Asia", Sales=4000 },new Customer { ID="N", City="Los Angeles", Country="USA", Region="North America", Sales=5000 },new Customer { ID="O", City="Cairo", Country="Egypt", Region="Africa", Sales=6000 },new Customer { ID="P", City="Tehran", Country="Iran", Region="Asia", Sales=7000 },new Customer { ID="Q", City="London", Country="UK", Region="Europe", Sales=8000 },new Customer { ID="R", City="Beijing", Country="China", Region="Asia", Sales=9000 },new Customer { ID="S", City="Bogotá", Country="Colombia", Region="South America", Sales=1001 },new Customer { ID="T", City="Lima", Country="Peru", Region="South America", Sales=2002 } };var customerIDs = from c in customers select c.ID ;var orderIDs = from o in orders select o.ID ;var customersWithOrders = customerIDs.Intersect（orderIDs）;Console.WriteLine（"Customers with Orders:"）;foreach （var item in customersWithOrders）{Console.Write（"{0} ", item）;}Console.WriteLine（）;Console.WriteLine（"Orders with no customers:"）;var ordersNoCustomers = orderIDs.Except（customerIDs）;foreach （var item in ordersNoCustomers）{Console.Write（"{0} ", item）;}Console.WriteLine（）;Console.WriteLine（"All Customer and Order IDs:"）;var allCustomerOrderIDs = orderIDs.Union（customerIDs）;foreach （var item in allCustomerOrderIDs）{Console.Write（"{0} ", item）;} Console.WriteLine（）;Console.Write（"Program finished, press Enter/Return to continue:"）;Console.ReadLine（）;}}}