public class Person
{
public int Id { get; set; }
public string Name { get; set; }
public Nullable<int> Age { get; set; }
public virtual ICollection<Pet> Pets { get; set; }
}若要求页面按如下格式展示数据，试考虑如何写Linq语句：
person1,pet1
person2,pet2
person3,pet3
简单的inner join可以用Join方法实现：
var data = context.People.Join(context.Pets, person => person.Id, pet => pet.Pid, (person, pet) => new { Name = person.Name, PName = pet.Name });针对这种特殊结构的对象，还可以用SelectMany来实现：
var data = context.People.SelectMany(person => person.Pets, (person, pet) => new { Name = person.Name, PName = pet.Name });这好像看不出优势，但若要实现left join，那就非用SelectMany不可了：
var data = context.People.GroupJoin(context.Pets, person => person.Id, pet => pet.Pid, (person, pets) => new { person = person, pets = pets }).SelectMany(item => item.pets.DefaultIfEmpty(), (item, pet) => new { Name = item.person.Name, PName = pet == null ? "-" : pet.Name });
//or
var data = context.People.SelectMany(person => person.Pets.DefaultIfEmpty(), (person, pet) => new { Name = person.Name, PName = pet == null ? "-" : pet.Name });SQL Server Profiler捕获对应sql语句：
Select
[Extent1].[Id] AS [Id],
[Extent1].[Name] AS [Name],
CASE WHEN ([Extent2].[Id] IS NULL) THEN N'-' ELSE [Extent2].[Name] END AS [C1]
FROM [dbo].[Person] AS [Extent1]
LEFT OUTER JOIN [dbo].[Pet] AS [Extent2] ON [Extent1].[Id] = [Extent2].[Pid]
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