Sql server 创建计算列的帮助（sql server 2008）

你好

在此表上创建计算列时需要一些帮助：

USE [ScienceWorksSummary]

GO

/****** Object:  Table [dbo].[Authors_Articles]    Script Date: 04/07/2011 10:38:55 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE TABLE [dbo].[Authors_Articles](
    [IdAuthor] [int] NOT NULL,
    [IdArticle] [int] NOT NULL,
    [Part] [float] NULL,
 CONSTRAINT [PK_Authors_Articles] PRIMARY KEY CLUSTERED 
(
    [IdAuthor] ASC,
    [IdArticle] 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

计算列（Part）的目的是获得每个作者的一部分作品，这些作者写了同一篇文章。那么比如说,， 如果idAuthor=1，idArticle=1，idAuthor=2，idArticle=1，则每个部分都必须为0.5

谢谢你的帮助

谢谢！！：）将1.0/count（）改为ROUND（（1.0/count（）），2），得到了我所需要的东西！

CREATE TABLE [dbo].[Authors_Articles](
    [IdAuthor] [int] NOT NULL,
    [IdArticle] [int] NOT NULL,
 CONSTRAINT [PK_Authors_Articles] PRIMARY KEY CLUSTERED 
(
    [IdAuthor] ASC,
    [IdArticle] ASC
))
GO
create function dbo.calcPart(@IdArticle int) returns float as
begin
return (Select 1.0/count(*) from [Authors_Articles] where IdArticle = @IdArticle)
end
GO
alter table Authors_Articles add Part as dbo.calcPart(IdArticle)