Selecting Food Calories from SPARQL - sparql

Question

I've started looking into SPARQL and I admit I find it very obscure and difficult.
I need to output the calories for all the foods.
I don't really understand the difference between the wd: wdt: p: and ps:
Similarly I am unclear on when to use P000 or Q000 ?
The best I got so far is:
SELECT ?food ?calories ?foodLabel ?caloriesLabel WHERE {
?food wdt:P31 wd:Q2095.
?food wdt:P31 ?calories.
SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
Which gives : Results
Any suggestion would be welcome

Answer 1

If you are willing to download a 1 GB RDF file and publish it at your own triplestore, this looks promising:
https://datahub.io/dataset/open-food-facts
Specifically, http://en.openfoodfacts.org/data/en.openfoodfacts.org.products.rdf (If English is your preferred languague.)
I say download and publish as Googling suggests these data aren't already exposed at any public endpoint.
You will likely have to use different classes and predicates, compared to WikiData.
Hey, this is pretty neat!
SELECT *
WHERE
{ GRAPH <http://openfoodfacts.org>
{ ?s a <http://data.lirmm.fr/ontologies/food#FoodProduct> ;
<http://data.lirmm.fr/ontologies/food#name> ?fn ;
<http://data.lirmm.fr/ontologies/food#energyPer100g> ?energy
}
}
LIMIT 9
gives
+------------------------------------------------------------------------------------------------------+---------------------------------------------+--------+
| s | fn | energy |
+------------------------------------------------------------------------------------------------------+---------------------------------------------+--------+
| http://world-en.openfoodfacts.org/product/9400547030446/heinz-big-n-chunky-chicken-corn | "Heinz Big'n Chunky Chicken & Corn" | "245" |
| http://world-en.openfoodfacts.org/product/9400550004847/sour-patch-kids-pascall | "Sour Patch Kids" | "1440" |
| http://world-en.openfoodfacts.org/product/9400550602487/brunch-mixed-berry-bar-cadbury | "Brunch Mixed Berry Bar" | "1810" |
| http://world-en.openfoodfacts.org/product/9400550646276/pascall-family-pack-sweets-fruit-bursts | "Pascall Family Pack Sweets Fruit Bursts" | "1427" |
| http://world-en.openfoodfacts.org/product/9400553011477/choc-thins-griffin-s | "Choc Thins" | "2010" |
| http://world-en.openfoodfacts.org/product/9400553438786/gingernuts-griffin-s | "Gingernuts" | "1810" |
| http://world-en.openfoodfacts.org/product/9400563448614/nice-natural-rosted-nut-bar-chocolate | "Nice & Natural Rosted Nut Bar - Chocolate" | "2060" |
| http://world-en.openfoodfacts.org/product/9400563740589/nut-bar-caramel-cashew-flavour-nice-natural | "Nut Bar - Caramel Cashew Flavour" | "1960" |
| http://world-en.openfoodfacts.org/product/9400563741784/superfruits-cranberry-blueberry-nice-natural | "Superfruits - Cranberry & Blueberry" | "1520" |
+------------------------------------------------------------------------------------------------------+---------------------------------------------+--------+