Re: update from select

On Wed, 29 Oct 2003, Gary Stainburn wrote:

> Hi folks,
>
> don't know if it's cos of the 17 hours I've just worked (sympathy vote please)
> but I can't get this one worked out
>
> I've got table names with nid as name id field and nallowfollow flag.
> I've got a vehicles table with vowner pointing at nid and a vallowfollow
> field.
>
> How can I update nallowfollow from the appropriate vallowfollow flag?

If vehicles.vowner is unique, something like this maybe (using extensions
to sql)?
update names set nallowfollow=vehicles.vallowfollow
from vehicles where vehicles.vowner=names.nid;

I think it'd be the follwoing in straight sql:
update names set nallowfollow=
(select vallowfollow from vehicles where vehicles.vowner=names.nid);

If it's not unique, what do you do if there are two vehicles with the same
vowner and different values for vallowfollow?