Re: some random() clarification needed

Ok, thanks for the clarification.

Marc MILLAS
Senior Architect
+33607850334
www.mokadb.com

On Tue, Jul 14, 2020 at 5:24 PM David G. Johnston <
david(dot)g(dot)johnston(at)gmail(dot)com> wrote:

> On Tue, Jul 14, 2020 at 8:15 AM Marc Millas <marc(dot)millas(at)mokadb(dot)com>
> wrote:
>
>> select id, prenom from prenoms where id=ceiling(random()*2582);
>>
>> expecting to get, allways, one line.
>> But its not the case.
>> around 15% of time I get 0 lines which is already quite strange to me.
>> but 10% of time, I get a random number of lines, until now up to 4.
>> even weirder (to me !)
>>
>> so, can someone please clarify ?
>>
>>
> You are basically asking:
>
> For each row in my table compare the id to some random number and if they
> match return that row, otherwise skip it. The random number being compared
> to is different for each row because random() is volatile and thus
> evaluated for each row.
>
> David J.
>