[Mondrian] Proposed additions to Mondrian schema syntax

[Julian Hyde]

> Eric wrote:
>
> In such a case, 
> grouping on the  
> property column is logically redundant and may safely be 
> eliminated if  
> the database permits queries to SELECT columns not in the GROUP BY.   
> MySQL allows this by default, though support for it can be 
> turned off  
> if desired.

You'll need a dialect property for this. MySQL is the only database I know
that supports this feature (even though it is consistent with the SQL
standard). Add a dialect test that makes sure that a database allows such
queries if and only if the dialect says that it does.

Julian