You are here: Re: very slow query (select count(*) from table) « MsSQL Server « IT news, forums, messages
Re: very slow query (select count(*) from table)

Posted by Erland Sommarskog on 02/17/06 00:18

Daniel Wetzler (Daniel.Wetzler@sig.biz) writes:
> I used the following statement :
>
> select count(1) from table. (for tables with PRIMARY KEY in first
> column)

COUNT(1) or COUNT(*) makes no difference.

> It seems that MS SQL has to load the whole table information if I say
> count(*).

As I said, if there is no non-clustered table, there is no better
option than to scan all data pages.


--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx

 

Navigation:

[Reply to this message]


Удаленная работа для программистов  •  Как заработать на Google AdSense  •  England, UK  •  статьи на английском  •  PHP MySQL CMS Apache Oscommerce  •  Online Business Knowledge Base  •  DVD MP3 AVI MP4 players codecs conversion help
Home  •  Search  •  Site Map  •  Set as Homepage  •  Add to Favourites

Copyright © 2005-2006 Powered by Custom PHP Programming

Сайт изготовлен в Студии Валентина Петручека
изготовление и поддержка веб-сайтов, разработка программного обеспечения, поисковая оптимизация