RE: SQL RAND function question

Loyd,

Yes it does. BUT if you call it 1000's of times, it doesn't given you an even distribution of numbers
between 0-11.

By definition, RAND() should given an even distribution.

Charles Wilt
Software Engineer
CINTAS Corporation - IT 92B
513.701.1307

wiltc@xxxxxxxxxx

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-
bounces@xxxxxxxxxxxx] On Behalf Of lgoodbar@xxxxxxxxxxxxxx
Sent: Tuesday, February 12, 2008 4:02 PM
To: midrange-l@xxxxxxxxxxxx
Subject: RE: SQL RAND function question

This gives me a range of 0-11.

select
date('2008-03-01') + cast(rand()*11 as decimal(2,0)) months
from sysibm/sysdummy1

Date expression
10/01/08

Loyd Goodbar
Senior programmer/analyst
BorgWarner
TS Water Valley
662-473-5713

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Wilt, Charles
Sent: Tuesday, February 12, 2008 12:25
To: Midrange Systems Technical Discussion
Subject: SQL RAND function question

All,



I'm attempting to use SQL's RAND() function to randomly assign a number
from 0-11. Actually, the 0-11
is used as a number of months to add to 2008-03-01.



Looking at a count of the results however seems to indicate I'm doing
something wrong:



Date count(*)

2008-03-01 13,234

2008-04-01 6,536

2008-05-01 13,262

2008-06-01 13,153

2008-07-01 13,474

2008-08-01 13,448

2008-09-01 13,245

2008-10-01 13,329

2008-11-01 13,358

2008-12-01 13,307

2009-01-01 13,542

2009-02-01 6,636



I'm thinking perhaps the way I'm going from the RAND() results to a
integer from 0-11 is the problem.
Anybody understand what I'm doing wrong?



myDate = date('2008-03-01') + cast(round((rand(12) * 11),0) as int)
months



Thanks!



Charles Wilt

Software Engineer

CINTAS Corporation - IT 92B

513.701.1307

wiltc@xxxxxxxxxx <mailto:wiltc@xxxxxxxxxx>




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