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 |
|
sparames
Starting Member
5 Posts |
 Posted - 2011-10-17 : 15:42:41
|
| Guys please help me explain this query in simple english. I need to write this for my research paper.SELECT TOP 3000 *FROM ExclusiveORDER BY Rnd(TimeValue(Now())*-10000000*[t1_ID1]); |
|
|
TG
Master Smack Fu Yak Hacker
6065 Posts |
Posted - 2011-10-17 : 16:56:09
|
| "TOP n" combined with "ORDER BY <random value>" has the effect of returning a random set of n rows. Assuming your table has more then 3000 rows you should expect a different result set every time the query runs even if the table is static.Be One with the OptimizerTG |
 |
|
|
sparames
Starting Member
5 Posts |
Posted - 2011-10-17 : 17:48:21
|
| Thanks a lot. Can you please throw more light on Rnd(TimeValue(Now())*-10000000*[t1_ID1]) |
|
|
|
TG
Master Smack Fu Yak Hacker
6065 Posts |
Posted - 2011-10-17 : 18:39:01
|
| that is the expression that generates a random number (which you are ordering by). It is 3 functions nested inside one another. The result of Now() is the argument to TimeValue(). That result is multiplied by the the product of -10000000 and the ID of that row - and that whole thing is used as the argument to the Rnd() function. It is designed to generate a different value for every row of the table and be deliberately inconsistent such that the next time you run the query the same row will generate a completely different value from the last run. What is your research paper about?Be One with the OptimizerTG |
|
|
|
sparames
Starting Member
5 Posts |
Posted - 2011-10-17 : 21:42:10
|
| My research paper is about analyzing a set of data for "Emergency Preparedness". I used this query from a forum to generate random records from my database in Access.. Now while writing the thesis a detailed description about the query is needed. So, I needed the meaning of this query in a sentence. |
|
|
|
|
|
|
Randon Number query explanation