> > But in a UNION ALL the distinctiveness isn't an issue, is it?
> True. We do not currently distinguish UNION from UNION ALL as far as
> datatype assignment rules go
<cut>
> I'm not sure if it'd be a good idea to do so or not. It'd
> make this particular example work the way you want, but otherwise it
> seems like making UNION ALL a special case would be a bit of a wart on
> the type system.
Well, in my case there's no situation where I don't know in advance where the
problem could occur, so it's easily avoided by proper typing of the first
null in the union all sequence.
Thanks for the explanation.
--
Best,
Frank.