If both the annotation and the value labels of an item match the pattern
the query
method for 'item' objects returns a list containing the annotation
and the value labels, otherwise if only the annotation or the value labels
match the pattern, either the annotation or the value labels are returned,
otherwise if neither matches the pattern, query
returns NULL
.
The methods of query
for 'data.set' and 'importer' objects return
a list of all non-NULL
query results of all items contained by these
objects, or NULL
.