Thursday, May 5, 2011

Paging in SQL 2

Regarding my post about Paging in SQL, I have found another easier way to include a column as a running number of the records. Hence, we do not need to create a temporary table, and the code will be much simpler.

I will use the same tables for example. In case you find difficulty finding the post about Paging in SQL, I include them here.

Here is the Create table Query:
CREATE TABLE dbo.MsUser
(  UserID CHAR(20) PRIMARY KEY,
   Username VARCHAR(100),
   Address VARCHAR(50),
   DivisionID INT
)

And here is the query to insert sample data:
-- Insert Data into MsUser
INSERT INTO dbo.MsUser VALUES ( 'Himura', 'Miss Himura', 'Earth', 3 )
INSERT INTO dbo.MsUser VALUES ( 'Selvia', 'Selvia', 'Indonesia', 2 )
INSERT INTO dbo.MsUser VALUES ( 'Superman', 'Clark Kent', 'Earth', 2 )
INSERT INTO dbo.MsUser VALUES ( 'SelviaHimura', 'Selvia Himura', 'Earth', 4 )
INSERT INTO dbo.MsUser VALUES ( 'Luck', 'Steven Luck', 'Indonesia', 1 )
INSERT INTO dbo.MsUser VALUES ( 'SuperLuck', 'Super Luck', 'United States', 1 )
INSERT INTO dbo.MsUser VALUES ( 'Selvi', 'Selvi', 'Indonesia', 1 )
INSERT INTO dbo.MsUser VALUES ( 'Lucky', 'Lucky Luke', 'United States', 3 )
INSERT INTO dbo.MsUser VALUES ( 'Steven', 'Steven', 'Earth', 4 )

Here is the data inserted to the tables:

Here is the query to get the data using paging:
DECLARE @PageSize INT, @PageNo INT
SELECT a.Username FROM (
    SELECT Username, RowNumber = ROW_NUMBER() OVER (ORDER BY Username) 
    FROM MsUser
) a WHERE a.RowNumber BETWEEN (@PageNo - 1 )* @PageSize + 1 AND @PageNo * @PageSize

Note that the key is in this part of code:

ROW_NUMBER() OVER (ORDER BY Username)


If the PageSize is set to 5 item per page, then the top 5 users will be displayed on Page 1 and the next 5 users will be displayed on Page 2.

e.g. 1
PageSize = 5, PageNo = 1
DECLARE @PageSize INT, @PageNo INT
SELECT  @PageSize = 5, @PageNo = 1
SELECT a.Username FROM (
    SELECT Username, RowNumber = ROW_NUMBER() OVER (ORDER BY Username) 
    FROM MsUser
) a WHERE a.RowNumber BETWEEN (@PageNo - 1 )* @PageSize + 1 AND @PageNo * @PageSize

The data retrieved on Page 1 will be:

e.g. 2
PageSize = 5, PageNo = 2
DECLARE @PageSize INT, @PageNo INT
SELECT  @PageSize = 5, @PageNo = 2
SELECT a.Username FROM (
    SELECT Username, RowNumber = ROW_NUMBER() OVER (ORDER BY Username) 
    FROM MsUser
) a WHERE a.RowNumber BETWEEN (@PageNo - 1 )* @PageSize + 1 AND @PageNo * @PageSize

And the data retrieved on Page 2 will be:

Share:

0 comments:

Post a Comment

About

Related Posts

Frame cannot Load - Content Security Policy Issue

Problem: You are using iframe to load a site from within a website, and the frame does not load. In my case, I am using https for both the...

About Me

My photo
Is an ordinary unNoticed man, with a little knowledge to share and high dreams to achieve. I'd be glad if I can help others, 'coz the only thing for the triumph of evil is for a good man to do nothing. I like English and Chinese language, and know a little about them. Hence, for me, most things can best be expressed in Chinese, some in English, and the rest in others ^^

About Blog

You can find a lot of debugging and deploying problems while developing applications in .NET and Visual Basic here. There are also some querying tips in SQL and typical source codes which might be useful shared here.

Popular Posts

Blogroll

Followers

Follow by Email