Label service
Items on Wikidata are identified by a unique Q number. Every item also has a label, which is the main name given to it in a particular language. The following query retrieves the films of the Star Wars series and their label.
#Star Wars films
SELECT ?item ?itemLabel
WHERE
{
?item wdt:P179 wd:Q22092344.
SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE]". }
}
Query explanation
In the SELECT clause, two variables are stated: ?item and ?itemLabel.
Label is a special string: it refers to the label of the item that is specified by the variable name. If we named our variable ?x, the variable for the label would be ?xLabel, if we named it ?film, the variable for the label would be ?filmLabel, and so on.
In the WHERE clause we see the same pattern for selection as before:
?item wdt:P179 wd:Q22092344.
In addition, we see in red the SERVICE command followed by the text (in blue):
wikibase:label { bd:serviceParam wikibase:language “[AUTO_LANGUAGE]”.
This code snippet is a kind of shortcut to a service which retrieves labels of items. In other words, if a variable in SELECT is named ?NAMELabel, WDQS retrieves the label for the item in variable ?NAME. This specialized service is very helpful, as it reduces the complexity of SPARQL queries that would otherwise be needed to achieve the same effect.
What is the AUTO_LANGUAGE?
The default language for WDQS is English, as indicated on the upper right hand corner. This affects both the language of the WDQS interface, as well as the label retrieved for items.
Run the query. Then change the auto language and run the query again.