db_or() returns a SelectQuery-object
Assuming an unchanged core codebase, and assuming you mean that your final line is returning a SelectQuery (not the db_or(), which returns a DatabaseCondition), the only way you could be seeing a SelectQuery is if you're inspecting the wrong variable, i.e. $filterSparten. The query will remain a query, you need to assign the results to something else:

$results = $filterSparten-&gt;condition($or)
  -&gt;execute()
  -&gt;fetchAssoc();


Inspecting $results should give you what you're expecting.