SQL Server 2005 has a ROW_NUMBER Function that can help with paging records for you database applications. ROW_NUMBER returns a sequential number, starting at 1, for each row returned in a resultset.

If I want the first page of 10 records from my log file sorted by Date DESC, I can use the ROW_NUMBER FUNCTION as follows:

SELECT Description, Date

FROM (SELECT ROW_NUMBER() OVER (ORDER BY Date DESC)

AS Row, Description, Date FROM LOG)

AS LogWithRowNumbers

WHERE Row >= 1 AND Row <= 10

The second page of 10 records would then be as follows:

SELECT Description, Date

FROM (SELECT ROW_NUMBER() OVER (ORDER BY Date DESC)

AS Row, Description, Date FROM LOG)

AS LogWithRowNumbers

WHERE Row >= 11 AND Row <= 20

If you have a lot of records, using TOP X in the inner SELECT clause may speed up things a bit as there is no use returning 1000 records if you are only going to grab records 11 through 20:

SELECT Description, Date

FROM (SELECT TOP 20 ROW_NUMBER() OVER (ORDER BY Date DESC)

AS Row, Description, Date FROM LOG)

AS LogWithRowNumbers

WHERE Row >= 11 AND Row <= 20

We can rap this up in a Stored Procedure as follows:

CREATE PROCEDURE dbo.ShowLog

@PageIndex INT,

@PageSize INT

AS

BEGIN

WITH LogEntries AS (

SELECT ROW_NUMBER() OVER (ORDER BY Date DESC)
AS Row, Date, Description

FROM LOG)

SELECT Date, Description

FROM LogEntries

WHERE Row between

(@PageIndex – 1) * @PageSize + 1 and @PageIndex*@PageSize

END

It is only available in SQL Server 2005, but it is a heck of a lot easier and more intuitive than creating temp tables and using other stored procedures that I have used in the past. However, if you want to target your application for SQL Server 2000 use, I would stick with a record paging solution that works for both SQL Server 2005 and SQL Server 2000 Databases.

Advertisements