Re: ACTION-24: aggregate functions with multiple answers

A couple of questions...

On May 11, 2009, at 10:36 AM, Seaborne, Andy wrote:

> Choices for dealing with this include:
>
> 1/ The value space for MIN is the value space of the first  
> encountered datatype and everything incompatible is ignored.
>
> 2/ The value space has to be given - there is no single "MIN"  
> operation:
> e.g. MIN(xsd:dateTime, ?x)

In what way is this different from the explicit casting approach  
previously mentioned (MIN(xsd:date(?x))? Do you imagine that they  
would handle differently values for which the casting fails?

> 3/ There is one answer per group for each datatype encountered in  
> the group.  This means multiple rows per group.

Could the same functionality be had by allowing a DATATYPE(?x)  
expression in the GROUP BY clause?

thanks,
.greg