Database

SELECT TOP 1 selectedFields FROM tablename WHERE matchConditions ORDER BY createdField DESC

select id, max(dateColumn) from tabelname group by id

John Simmons / outlaw programmer wrote:

I am of the current opinion that SQL sucks.

if object_id('tempdb..#DUAL')is not null
	DROP TABLE #DUAL

create table #DUAL
(
	ID int,
	datevalue datetime
)

insert into #DUAL (ID, datevalue)
	select id, max(datevalue)
	from metrics 
	group by ID

SELECT	
		a.ID
		,a.itemType
		,a.Title
		,a.Description
		,m.DateValue
FROM tableA a, metrics m, #Dual d
WHERE a.id = d.id AND a.ID = m.ID AND m.datevalue = d.datevalue

drop table #DUAL

SELECT a.Id,
	a.ItemType,
	a.Title,
	a.Description,
	m.DateValue
FROM TableA a
LEFT JOIN
(
	SELECT Id, 
		MAX(DateValue) as DateValue 
	FROM Metrics
	GROUP BY Id
) m ON m.Id = a.Id

if object_id('tempdb..#TableA')is not null
	DROP TABLE #TableA
go 
if object_id('tempdb..#Metrics')is not null
	DROP TABLE #Metrics
go 

create table #TableA
(
	Id int,
	ItemType char(1),
	Title varchar(50),
	Description varchar(100)
)
go

create table #Metrics
(
	ID int,
	TableAId int,
	datevalue datetime
)
go

insert into #TableA (ID, ItemType, Title, Description) values (1, 'A', 'First Title', 'First Description');
insert into #TableA (ID, ItemType, Title, Description) values (2, 'A', 'Second Title', 'Second Description');
insert into #TableA (ID, ItemType, Title, Description) values (3, 'B', 'Third Title', 'Third Description');
go

insert into #Metrics (ID, TableAId, datevalue) values (1, 1, '2010-01-01');
insert into #Metrics (ID, TableAId, datevalue) values (2, 1, '2010-01-02');
insert into #Metrics (ID, TableAId, datevalue) values (3, 3, '2010-01-03');
insert into #Metrics (ID, TableAId, datevalue) values (4, 2, '2010-01-04');
insert into #Metrics (ID, TableAId, datevalue) values (5, 2, '2010-01-05');
insert into #Metrics (ID, TableAId, datevalue) values (6, 3, '2010-01-06');
insert into #Metrics (ID, TableAId, datevalue) values (7, 1, '2010-01-07');
insert into #Metrics (ID, TableAId, datevalue) values (8, 2, '2010-01-08');
insert into #Metrics (ID, TableAId, datevalue) values (9, 1, '2010-01-09');
insert into #Metrics (ID, TableAId, datevalue) values (10, 3, '2010-01-10');
insert into #Metrics (ID, TableAId, datevalue) values (11, 3, '2010-01-11');
insert into #Metrics (ID, TableAId, datevalue) values (12, 1, '2010-01-12');
go

SELECT	
		a.ID
		,a.itemType
		,a.Title
		,a.Description
		,m.DateValue
FROM #TableA a
left join
(
	select tableaid,
		MAX(datevalue) as datevalue
	from #Metrics
	group by tableaid
) m on m.tableaid = a.id
go

drop table #Metrics
go 
drop table #TableA
go

/****** Object:  Table [dbo].[ArticleMetrics]    Script Date: 03/21/2010 17:20:15 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[ArticleMetrics](
	[ArticleID] [nvarchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
	[Votes] [int] NOT NULL,
	[Bookmarks] [int] NOT NULL,
	[Downloads] [int] NOT NULL,
	[Popularity] [decimal](5, 2) NOT NULL,
	[Rating] [decimal](5, 2) NOT NULL,
	[LastUpdated] [smalldatetime] NOT NULL,
	[Views] [int] NOT NULL,
	[DateScraped] [datetime] NOT NULL
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[ArticleMetrics]  WITH CHECK ADD  CONSTRAINT [FK_ArticleMetrics_Articles] FOREIGN KEY([ArticleID])
REFERENCES [dbo].[Articles] ([ArticleID])
GO
ALTER TABLE [dbo].[ArticleMetrics] CHECK CONSTRAINT [FK_ArticleMetrics_Articles]
USE [CPAM]
GO


/****** Object:  Table [dbo].[Articles]    Script Date: 03/21/2010 17:20:46 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
CREATE TABLE [dbo].[Articles](
	[ArticleID] [nvarchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
	[ArticleType] [int] NOT NULL,
	[Title] [nvarchar](255) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
	[Description] [varchar](512) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
	[DatePosted] [smalldatetime] NOT NULL,
	[Active] [bit] NOT NULL,
	[LastScraped] [datetime] NOT NULL,
 CONSTRAINT [PK_Articles] PRIMARY KEY CLUSTERED 
(
	[ArticleID] ASC
)WITH (PAD_INDEX  = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
GO
SET ANSI_PADDING OFF

SELECT a.*,
	lm.*
FROM dbo.Articles AS a
	CROSS APPLY 
		(SELECT TOP 1 m.*
		 FROM dbo.ArticleMetrics AS m
		 WHERE m.ArticleId = a.ArticleId
		 ORDER BY m.DateScraped DESC) AS lm

select id, max(dateColumn) from tabelname group by id

SELECT *
FROM TableA a
JOIN TableB b
    ON b.ID = a.ID

Jörgen Andersson wrote:

Sometimes people don't want the admin to be able to see the data.

Jörgen Andersson wrote:

Being an admin I find that disturbing.