Re: Using random() in update produces same random value for all

Olleg Samoylov <splarv@ya.ru> writes:
> Looked like random() is "volatile", but in subselect it works like "stable".

The point here is that that's an uncorrelated subselect --- ie, it
contains no outer references --- so it need not be, and is not,
re-evaluated at every outer row.

            regards, tom lane