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From:Arthur Fuller Date:July 15 2011 6:12pm
Subject:Re: MySQL RAND() Issues [was Re: How to Shuffle data]
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This would be sooo much simpler to solve in MS-SQL, given the function
NewID(), which is guaranteed to return a unique value. I have used this in a
few web sites and it works splendidly; something along the lines of

SELECT TOP 10 *, NewID() FROM User_Messages
ORDER BY NewID

which is guaranteed to produce a new GUID for each row, and then order by
said values. It is not guaranteed to produce 10 results different than the
previous SELECT, but nevertheless works extremely well on a web site.

I have Googled this and that but not yet succeeded in finding the equivalent
in the MySQL world. In theory, this should be relatively easy, since the
GUID docs are available, but I'm out of my depth here on how to write the
MySQL equivalent function.

In case anyone has devised a MySQL equivalent for the NewID() function, we
could all massively benefit from your posting of same.

TIA,
Arthur

On Fri, Jul 15, 2011 at 1:40 PM, Jan Steinman <Jan@stripped> wrote:

> > From: Reindl Harald <h.reindl@stripped>
> >
> > do not use any random-functions of mysql even if they exists
> > http://bugs.mysql.com/bug.php?id=59253
>
> Of course, it depends on the desired quality of randomness needed.
>
> I'm using RAND() to select random quotations to put at the end of emails. I
> can easily repeat the process by re-selecting the "Signature:" menu in Apple
> Mail. Problem is, I often notice that doing so cycles through several
> similar signatures in a decidedly non-random way!
>
> (You can demo this by sending email to <Quote@stripped>, with a
> search term in the Subject: line.)
>
> But of course, a nuclear plant is not going to melt down because of my
> signature line.
>
> So RAND() can be useful, but it is not really very random, and should be
> used with caution. My guess is that it's using Knuth's linear congruential
> algorithm that has well-known problems, but that unfortunately has been
> hidden deep in system code libraries since "Fundamental Algorithms" was
> published in 1968.
>
> ----------------
> World events tend to be driven by loose coalitions of economic, political,
> and military interests, which function like guilds of species in an
> ecosystem. These guilds generate patterns of events that meet the interests
> of these coalitions, without there being any unity of purpose or clear plan.
> When powerful players accept they are not all-powerful, they increase their
> effectiveness, but are also able to deny and cover any responsibility for
> the adverse outcomes of those actions. -- David Holmgren
> :::: Jan Steinman, EcoReality Co-op ::::
>
>
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Thread
MySQL RAND() Issues [was Re: How to Shuffle data]Jan Steinman15 Jul
  • Re: MySQL RAND() Issues [was Re: How to Shuffle data]Arthur Fuller15 Jul
    • Re: MySQL RAND() Issues [was Re: How to Shuffle data]Michael Dykman15 Jul
    • Re: MySQL RAND() Issues [was Re: How to Shuffle data]Dan Nelson15 Jul
  • Re: MySQL RAND() Issues [was Re: How to Shuffle data]Reindl Harald15 Jul