Re: UPDATE using query; per-row function calling problem

Rory Campbell-Lange <rory@campbell-lange.net> writes:
> I'm doing an UPDATE something like this:
>     UPDATE
>         slots
>     SET
>         a = 'a'
>         ,b = (SELECT uuid_generate_v1())
>     WHERE
>         c = TRUE;

> Each updated row in slots is getting the same value for b.

That's Postgres' interpretation of an uncorrelated sub-SELECT: there's
no reason to do it more than once, so it doesn't.

> Is there a way of getting a per-row value from uuid_generate_v1()
> without doing a PL loop?

Drop the word "SELECT".  Why did you put that in in the first place?

            regards, tom lane