Thread:Help talk:Selecting pages/Selecting pages that have the same value set for a property

On the page for a movie (directed by a director) I would like to display a list of other movies directed by the same director. I.e. other pages in the category:Movies that have the same value set for the property:Directed by.

The above example produces a datatable with other movies directed by the same director, but it also outputs a warning (caused by the |-sign probably... WARNING: part "" of query not understood, may cause unexpected results...). Is there a better way for doing this?

Regards, Martin