ORDER BY RAND() - Not random enough

ealderton

I am displaying a random list of properties on

http://www.stayindependently.com/index1.htm

(this is a test page)

You'll notice that on clicking view properties it usually places the same properties at the bottom of the list - in other words, the RAND() function does not seem to produce a 'random' result.

Can anyone help me on this?

at the moment, simplistically, the query is

SELECT * FROM SELFCATERING ORDER BY RAND()

sometimes there's a where in the middle of that, but that isn't important.

Thanks folks!

Regards

Elizabeth

nnichols

You could try this -

SELECT *, MD5( RAND( NOW( ) ) ) AS myRandom
FROM SELFCATERING ORDER BY myRandom

It does seem to give completely random results.

nnichols

Could get painfully slow. Just tried it with a table of just under 15k rows and it took over 1 sec

ealderton

Vunderbar

Yes, brilliant - it works.

Not too worried about speed - we don't expect to have huge numbers of properties, and if we did have we'd probably make some of the searches compulsory.

Thank you ever so much

Regards

Elizabeth

gte806e

Try seeding the sql Rand() with a random number generated using php's random number generation.

Jesse

ealderton

At the moment I'm using

srand((double) microtime() * 1000000);

would that be sufficient do you think?

Regards

Elizabeth