RE: SQL RAND function question

Elvis,

I'm using a seed so that as I rerun the thing, I get the same results...

Using INT(rand() * 12), gives me a better distribution, except for the fact that I get 6 values of 12,
when I only want 0-11.

As I said in my other post 11.99999 seemed to give me what I needed.

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 Elvis Budimlic
Sent: Tuesday, February 12, 2008 1:50 PM
To: 'Midrange Systems Technical Discussion'
Subject: RE: SQL RAND function question

I don't see anything wrong that jumps out at me, so I'll ask some
questions.

Why are you using a seed value?
What are you counting and does the sum of individual counts add up to the
total count?

I might rewrite that line as:

myDate = date('2008-03-01') + INT(rand() * 12) months

but I don't think that'll have any effect on the counts you're seeing.

Elvis

Celebrating 11-Years of SQL Performance Excellence on IBM i5/OS and OS/400
www.centerfieldtechnology.com


-----Original Message-----
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

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