如何从几个表

Question

选择值

我的三个表的结构是：使用

USE [DB_OrderV2] 
GO 

/****** Object: Table [dbo].[tblPageInfo] Script Date: 07/24/2010 23:16:18 ******/ 
SET ANSI_NULLS ON 
GO 

SET QUOTED_IDENTIFIER ON 
GO 

CREATE TABLE [dbo].[tblPageInfo](
    [Code] [int] IDENTITY(1,1) NOT NULL, 
    [PageID] [smallint] NOT NULL, 
    [PageName] [nvarchar](80) NOT NULL, 
    [Description] [nvarchar](80) NOT NULL, 
    [Status] [tinyint] NOT NULL, 
    [CreateUserID] [smallint] NULL, 
    [CreateDate] [smalldatetime] NULL, 
    [UpdateUserID] [smallint] NULL, 
    [UpdateDate] [smalldatetime] NULL, 
CONSTRAINT [PK_tblPageInfo] PRIMARY KEY CLUSTERED 
(
    [PageID] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
) ON [PRIMARY] 

GO 


USE [DB_OrderV2] 
GO 

/****** Object: Table [dbo].[tblUserType] Script Date: 07/24/2010 23:17:42 ******/ 
SET ANSI_NULLS ON 
GO 

SET QUOTED_IDENTIFIER ON 
GO 

CREATE TABLE [dbo].[tblUserType](
    [Code] [int] IDENTITY(1,1) NOT NULL, 
    [UserTypeID] [smallint] NOT NULL, 
    [UserType] [nvarchar](50) NOT NULL, 
    [Status] [tinyint] NULL, 
    [CreateUserID] [smallint] NULL, 
    [CreateDate] [smalldatetime] NULL, 
    [UpdateUserID] [smallint] NULL, 
    [UpdateDate] [smalldatetime] NULL, 
CONSTRAINT [PK_tblUserType] PRIMARY KEY CLUSTERED 
(
    [UserTypeID] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
) ON [PRIMARY] 

GO 


USE [DB_OrderV2] 
GO 

/****** Object: Table [dbo].[tblUserInfo] Script Date: 07/24/2010 23:18:33 ******/ 
SET ANSI_NULLS ON 
GO 

SET QUOTED_IDENTIFIER ON 
GO 

CREATE TABLE [dbo].[tblUserInfo](
    [Code] [int] IDENTITY(1,1) NOT NULL, 
    [UserID] [smallint] NOT NULL, 
    [UserName] [nvarchar](50) NOT NULL, 
    [LoginName] [nvarchar](50) NOT NULL, 
    [Password] [nvarchar](50) NOT NULL, 
    [UserTypeID] [smallint] NOT NULL, 
    [Status] [tinyint] NOT NULL, 
    [ActiveDate] [datetime] NULL, 
    [CreateUserID] [smallint] NULL, 
    [CreateDate] [smalldatetime] NULL, 
    [UpdateUserID] [smallint] NULL, 
    [UpdateDate] [smalldatetime] NULL, 
CONSTRAINT [PK_tblUserInfo_1] PRIMARY KEY CLUSTERED 
(
    [UserID] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
) ON [PRIMARY] 

GO 

上表中我需要一个选择查询，选择若干领域。但是怎么样？

query = this.Context.tblUserInfos 
       .Where(p => p.Status == 1) 
       .Select(p => new { p.tblUserType.UserTypeID,p.tblUserType.UserType,}); 
      return query; 

上述LINQ查询效果很好，但在这里我需要从tblUserRole表，页面名称从tblPageInfo表中选择UserRoleID。什么写在上面的查询选择那些领域。

Answer 1

就像在SQL中，你会想要使用连接。所以像

query = from p in Context.tblUserInfos 
     join u in Context.tblUserRole Where p.UserRoleID equals u.UserRoleID 
     join n in context.tblPageInfo where p.PageName equals n.PageName 
     where p.Status == 1 
     select new {p.tblUserType.UserTypeId, p.tblUserType.UserType, u.UserRoleId, n.PageName}; 

我不能很好地解析你想从每张表上加入，但这应该让你开始。

编辑

我想我可能已经得到了我的语法困惑。

直线上升Labmda版本

query = Context.tblUserInfos 
     .Join(Context.tblUserRole, info => info.UserRoleID, user => user.UserRoleID, (info, user) => new {Info = info, User = user}) 
     .Join(Context.tblPageInfo, info2 => info2.PageName, name => name.PageName, (info2, name) => new {Info2 = info2, Name = name}) 
     .Where(p => p.Status == 1) 
     .Select(p => new { p.tblUserType.UserTypeID,p.tblUserType.UserType, User, Name}); 

我没有测试过这一点，但我认为这是正确的。