Nando Dessena wrote:

>
> A> The join will produce one name for each course the student takes.
> A> Which one is meant to be the mentor?
>
> no one. A run time error should be thrown, much like when you are required to
> use a singleton select and you don't. That's what databases which
> support this useful (although admittedly ugly) extension do, AFAIK.

The definition of a singleton select is pretty well known. What's the
definition of a join that returns at most one pair of rows for each row
in the left hand side of the join? Do you have a sample from the
documentation of one of these beasts?


Regards,


Ann