entity framework在应该进行INNER JOIN（多个表）时生成LEFT OUTER JOIN

我有以下奇怪的行为：

public class Result { [Key] public int Id { get; set; } public int RuleId { get; set; } public int UserId { get; set; } [ForeignKey("RuleId")] public virtual Rule Rule { get; set; } [ForeignKey("UserId ")] public virtual User User { get; set; } } public class Rule { [Key] public int Id { get; set; } public string Name { get; set; } // More columns } public class User { [Key] public int Id { get; set; } public string Name { get; set; } // More columns } 

如果我做：

 ctx.Results.AsQueryable().Select(r => new { r.Rule.Name } ).ToList(); 

在SQL Server中执行的查询在Rule上执行内部联接：

 SELECT [Extent1].[RuleId] AS [RuleId], [Extent2].[Name] AS [Name] FROM [dbo].[result] AS [Extent1] INNER JOIN [dbo].[rule] AS [Extent2] ON [Extent1].[RuleId] = [Extent2].[Id] 

但如果我这样做：

 ctx.Results.AsQueryable().Select(r => new { rn = r.Rule.Name, un = r.User.Name } ).ToList(); 

执行的查询在规则上执行内连接，但在用户上执行OUTER JOIN。

 SELECT [Extent1].[UserId] AS [UserId], [Extent2].[Name] AS [Name], [Extent3].[Name] AS [Name1] FROM [dbo].[result] AS [Extent1] INNER JOIN [dbo].[rule] AS [Extent2] ON [Extent1].[RuleId] = [Extent2].[Id] LEFT OUTER JOIN [dbo].[user] AS [Extent3] ON [Extent1].[UserId] = [Extent3].[Id] 

当然这是错的？

Answer 1

答案是：entity framework中的错误。 下载最新版本，它们都是内部联接。