TABLESAMPLE

Question

TABLESAMPLE

ss-457805

SSCertifiable

Points: 5872
More actions
June 19, 2009 at 3:03 am

#133021

Why do we use tablesample if it only gives approx number of rows.
What is the advantage of using tablesample instead of Top?
blog: http://sarveshsingh.com Twitter: @sarveshsing

Viewing 5 posts - 1 through 4 (of 4 total)

You must be logged in to reply to this topic. Login to reply

joeroshan SSChampion Points: 10377 More actions · Answer 1

Table sample returns random set of rows. There is no guarantee for the number of records returned. It can be used for sampling

While top will give you the same set of records for each executes, provided the data is not changed

----------------------------------------------------------------------------------------------------------------------------------------------------
Roshan Joe

Jeff Moden -Forum Etiquette: How to post data/code on a forum to get the best help[/url]

ss-457805 SSCertifiable Points: 5872 More actions · Answer 2

Thank you for ur reply joe, but i am still not clear.. What do u mean it can be used for sampling?? Could you provide me with some examples.

Many thanks.

blog: http://sarveshsingh.com Twitter: @sarveshsing

joeroshan SSChampion Points: 10377 More actions · Answer 3

Here is a good article I found when I goggled

http://www.mssqltips.com/tip.asp?tip=1308

----------------------------------------------------------------------------------------------------------------------------------------------------
Roshan Joe

Jeff Moden -Forum Etiquette: How to post data/code on a forum to get the best help[/url]

ss-457805 SSCertifiable Points: 5872 More actions · Answer 4

Thank you Joe,

It does make sense after reading the article.

blog: http://sarveshsingh.com Twitter: @sarveshsing