Please start any new threads on our new
site at https://forums.sqlteam.com. We've got lots of great SQL Server
experts to answer whatever question you can come up with.
| Author |
Topic |
|
xpandre
Posting Yak Master
212 Posts |
 Posted - 2011-05-11 : 12:56:37
|
| Hi,What would be the most efficient way to get a random sample set of data from a huge set of data from a table.For eg :I need to get the no of call made by a subscriber between date 01/01/2011 and 21/04/2011. In my DB, I would have more than a million records. But I want just 2000 of that. But I need the dates of the call to be truly scattered in the time interval given.like I need to have at least 1 record from Jan, 1 record from Feb, 1 record from March and 1 record from April.I tried using NEWID() --> But this is very costly.I tried using BINARY_CHECKSUM --> But this for some reason doesn't get me the sample as i want..like it gets me all 2000 from Jan and nothing from other months.Thank you guys in advanceSam |
|
|
sunitabeck
Master Smack Fu Yak Hacker
5155 Posts |
Posted - 2011-05-11 : 13:08:58
|
| Is the cost for the newid() method in generation of the newid, or in the sorting based on newid? If it is in the sorting, you might try crypt_gen_random function instead of newid. It generates hexadecimal number (of any length you specify), so sorting may be faster. |
 |
|
|
Lamprey
Master Smack Fu Yak Hacker
4614 Posts |
|
|
xpandre
Posting Yak Master
212 Posts |
Posted - 2011-05-12 : 03:47:23
|
| Thank you :-)..i shall try these and let you know my results.. |
|
|
|
|
|
|
get random samples