存储过程使用默认值

USE [Test_Blog]
GO
/****** Object:  StoredProcedure [dbo].[db_blog_tags_gettags]    Script Date: 06/16/2010 13:58:54 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:  <Author,,Name>
-- Create date: <Create Date,,>
-- Description: <Description,,>
-- =============================================
ALTER PROCEDURE [dbo].[db_blog_tags_gettags]
(
 @field nvarchar(500)='*',
 @where nvarchar(500)
)
AS
BEGIN
 declare @sql nvarchar(3000)
 if @where<>''
      set @sql =' select top 1  '+@field+' from  tags where '+@where+''
  else
   set @sql=' select top 1  '+@field+' from  tags'
  exec(@sql)
END

exec db_blog_tags_gettags  @where= 'id>3'