December 7, 2010 at 2:50 am
SwePeso (12/6/2010)
It seems the dual TOP/ORDER BY was the most efficient approach by the time.I tested the new Denali OFFSET/FETCH and I got the exact same number of reads for @StartRow = 5000, but 2 ms instead of 4 ms.
SELECTNumber
FROMdbo.TallyNumbers
ORDER BYNumber
OFFSET@StartRow - 1 ROWS
FETCH NEXT50 ROWS ONLY
This is unreleased SQL Server 2011 functionality only, right?
December 7, 2010 at 3:27 am
SwePeso (12/6/2010)
It seems the dual TOP/ORDER BY was the most efficient approach by the time.I tested the new Denali OFFSET/FETCH and I got the exact same number of reads for @StartRow = 5000, but 2 ms instead of 4 ms.
SELECTNumber
FROMdbo.TallyNumbers
ORDER BYNumber
OFFSET@StartRow - 1 ROWS
FETCH NEXT50 ROWS ONLY
My take on the Denali paging....
http://sqlblogcasts.com/blogs/sqlandthelike/archive/2010/11/10/denali-paging-is-it-win-win.aspx
and
http://sqlblogcasts.com/blogs/sqlandthelike/archive/2010/11/19/denali-paging-key-seek-lookups.aspx
November 7, 2011 at 11:45 pm
This is good. But i wanted to ask, what about the situation in which, say there are only 5 records in the table, and you ask for page number 2 with page size 10?
In that case there is no data returned to you, and you will not get to know how many records are there, in the table.
October 26, 2013 at 12:58 pm
I'm quite surprised that the "holy grail of paging" doesn't mention the (granted a bit less popular) "seek method" as described here:
http://blog.jooq.org/2013/10/26/faster-sql-paging-with-jooq-using-the-seek-method/[/url]
Take the following example:
SELECT TOP 10 first_name, last_name, score
FROM players
WHERE (score < @previousScore)
OR (score = @previousScore AND player_id < @previousPlayerId)
ORDER BY score DESC, player_id DESC
The @previousScore and @previousPlayerId values are the respective values of the last record from the previous page. This allows you to fetch the "next" page. If the ORDER BY direction is ASC, simply use > instead.
With the above method, you cannot immediately jump to page 4 without having first fetched the previous 40 records. But often, you do not want to jump that far anyway. Instead, you get a much faster query that might be able to fetch data in constant time, depending on your indexing. Plus, your pages remain "stable", no matter if the underlying data changes (e.g. on page 1, while you're on page 4).
This is the best way to implement paging when lazy loading more data in web applications, for instance.
October 26, 2013 at 6:16 pm
Sorry, but at first blush I think parameter sniffing (without some other query addition) could totally screw you here. Maybe an OPTION (RECOMPILE) could help, depending on what version of SQL Server you are on.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service
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