On Mon, Feb 28, 2005 at 17:46:43 +0100,
Karsten Hilbert <Karsten.Hilbert@gmx.net> wrote:
>
> There are 5 vaccinations in a given vaccination schedule.
>
> Patient had 3 shots.
>
> I want the view to show me that shot 4 and 5 are missing
> without having to enter the cardinality of the vaccination in
> the original data.
For this kind of task you usually want to use a left (or right) join.