Allow Asc/Desc in GROUP_CONCAT

[kouralex]

I occasionally find myself in a position where I have the need to sort the values that fall into GROUP_CONCAT. Although this is possible to achieve otherwise, I'd prefer to have a simple sorting option added to GROUP_CONCAT, maybe with a language-aware extra option, if possible.

[hartig]

While I agree that this would be a useful feature, I believe that adding features like this is beyond the scope of the current working group. So, maybe for SPARQL 1.3, but not for 1.2.

As an aside (and not related to the work of the current WG!!): In the SPARQL-CDTs extension that @kasei and I have been proposing, we have a FOLD aggregate which is somewhat similar to GROUP_CONCAT and it contains an optional GROUP BY clause. Our SPARQL-CDTs spec contains an the informal description of the FOLD aggregate where the second example illustrates the use of FOLD with GROUP BY. The subsections of Section 11 of that spec define how exactly the SPARQL spec would need to be extended to integrate FOLD, and extending GROUP_CONCAT with a GROUP BY feature may be done in a very similar way.

[kasei]

@hartig I assume you meant ORDER BY, not GROUP BY?

[hartig]

Oops. Yes, of course, ORDER BY

[TallTed]

Please see w3c/sparql-dev#9. This is not a new wish (and it's one I share).

[hartig]

How stupid of me. That SPARQL-DEV proposal is even from @kasei himself (and, as I mention above, I am in favor of this extension itself).

The question is, do the other WG members here agree with my aforementioned assessment that this change is beyond the scope of the WG?

[afs]

The question is, do the other WG members here agree with my aforementioned assessment that this change is beyond the scope of the WG?

Yes. Despite it being a reasonable request, the current charter is restrictive.

These new features quite often end up with a noticeable amount of refinement - they would take time to investigate. (Is there a better way to address the use case? Is there a more general feature lurking here? e.g. return lists or nested tables?)

The WG follow-on (which isn't defined in detail) may well allow it (a possible SPARQL 1.3)

Out of Scope
The following features are out of scope, and will not be addressed by this Working group.

Adding other improvements or extensions to RDF or SPARQL. Given the number of recommendations that this Working Group needs to update, it is important to keep its scope very focused.