Question

我需要查询帮助。我想返回一个实体列表，对于每个实体，我需要两个计数。

使用表格生成实体：

    /****** Objet :  Table [dbo].[Messages]    Date de génération du script : 03/12/2013 15:31:06 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
DROP TABLE [dbo].[Messages]
Go
CREATE TABLE [dbo].[Messages](
    [MessageID] [int] IDENTITY(1,1) NOT NULL,
    [UserCreation] [nvarchar](20) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [DateCreation] [datetime] NOT NULL  DEFAULT (getdate()),
    [UserModif] [nvarchar](20) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [DateModif] [datetime] NOT NULL  DEFAULT (getdate()),
    [Timestamp] [timestamp] NOT NULL,
    [Notification] [bit] NOT NULL  DEFAULT ((0)),
    [BounceTraite] [bit] NOT NULL  DEFAULT ((0)),
 CONSTRAINT [PK_Messages] PRIMARY KEY CLUSTERED 
(
    [MessageID] ASC
)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]

GO
/****** Objet :  Table [dbo].[MessageLocalisations]    Date de génération du script : 03/12/2013 15:31:06 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
DROP TABLE [dbo].[MessageLocalisations]
Go
CREATE TABLE [dbo].[MessageLocalisations](
    [MessageID] [int] NOT NULL,
    [CodeLocalisation] [char](5) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [From] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [Subject] [nvarchar](255) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [Message] [nvarchar](max) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [TargetedAudience] [nvarchar](255) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
 CONSTRAINT [PK_MessageLocalisations] PRIMARY KEY CLUSTERED 
(
    [MessageID] ASC,
    [CodeLocalisation] ASC
)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]

GO
SET ANSI_PADDING OFF
GO
/****** Objet :  Table [dbo].[MessageRecipients]    Date de génération du script : 03/12/2013 15:31:06 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
DROP TABLE [dbo].[MessageRecipients]
Go
CREATE TABLE [dbo].[MessageRecipients](
    [MessageID] [int] NOT NULL,
    [Recipient] [nvarchar](20) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [DateRead] [datetime] NULL,
    [Email] [nvarchar](60) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
    [Bounce] [bit] NOT NULL,
    [DateCreation] [datetime] NOT NULL,
    [DateModif] [datetime] NOT NULL ,
 CONSTRAINT [PK_MessageRecipients] PRIMARY KEY CLUSTERED 
(
    [MessageID] ASC,
    [Recipient] ASC
)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]

GO
SET ANSI_PADDING OFF
GO

在我的例子中，我的实体是消息。我需要收件人数和已阅读邮件的收件人数：

    (From msg In context.Messages.Include("MessageLocalisations")
                         Let countRecipients = msg.MessageRecipients.Count
                         Let countRecipientsRead = msg.MessageRecipients.Where(Function(x) x.DateRead.HasValue).Count
                         Where (msg.UserCreation.Equals(user, StringComparison.OrdinalIgnoreCase))
                         Group By msg.MessageID Into Group
                         Select msg, Group).ToList()

我的例子不起作用。我的select语句错误，他不识别msg。在LINQ中，我不确定Group如何工作以及当我使用Group By时如何选择工作。

我想要的结果是一个消息列表，其中包括MessageLocalisations，每封邮件的收件人数，读取每封邮件的收件人数。

感谢您的帮助！在SQL中这很简单...... :(

Answer 1

这是最终解决我问题的查询：

context.MessageSecuriseJeu.Include("MessageSecuriseLocalisations").
                            Where(Function(w) w.UtilisateurCreation.Equals(codeUtilisateurExpediteur, StringComparison.CurrentCultureIgnoreCase)).
                            Select(Function(msg) New With {.msg = msg, .nbrDest = msg.MessageSecuriseDestinataires.Count, .nbrLu = msg.MessageSecuriseDestinataires.Where(Function(w) w.DateLecture.HasValue).Count}).tolist()

如何使用group by和两个计数查询Linq to Entities

1 个答案: