Re: question on UNION

On 6/5/07, Steve Harris <swh@ecs.soton.ac.uk> wrote:
> if that works then you have a bug. The behaviour of SPARQLs UNION is not
> very natural from a relation algebra p.o.v., and this may have confused
> developers familiar with that.
>

Isn't it just outer union?  And isn't outer union just part of SQL 92.
 And isn't SQL 92 implemented by most (all?) databases.