"JOIN"-ing information from multiple categories ???

From semantic-mediawiki.org

How is it possible to join information from several pages in an inline query?

Her is an example: Events takes place in locations. I have to categories: Events and Locations, in order to prevent data redundancy. Every event is a page with information about the event, and every location is a page with information about the location as well as it's coordinates. How can I make an inline query that lists events as well as the coordinates where they take place, although the information about the corrdinates is not shown on the event page (where you can only find information about the location-page of the event).

{{#ask: [[Category:Events]] |?Has starttime |?Has endtime |?Has location <--- of type page |?Har more information... |format=filtered }}

is it possible to combine with this...

{{#ask: [[Category:Locations]] |?Has adress |?Has contact person |?Has coordinates |?Has moore information |format=datatable }}

In SQL you would normally do this with a JOIN is there an equivalent way to join information in SMW? into something like this...

{{#ask: [[Category:Events]] JOIN [[Category:Locations]] ...ON Event.Location = Location |?Event.Has starttime |?Event.Has endtime |?Location.Has coordinates |format=filtered }}

I am sure that wont work, but I hope you understand what I want to achieve.

Take care! Martin

Has location = Location

16:54, 7 October 2012

Property chains with the syntax Has location.Has coordinates work in conditions, but unfortunately not in columns (and why?).

You can use template format instead, with a template containing a {{#show:}} call. Yes, the performance will be terrible.

06:29, 8 October 2012

If the result doesn't have too many events the performance can be perfectly acceptable. I do such things with the template format all the time and I have no complaints about performance. So the performance can be terrible yes, but can also fine.

17:05, 18 October 2012