Cheatsheets:SPARQL: Difference between revisions

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For querying a different Wikibase instance (endpoint, prefixes, label service),
For querying a different Wikibase instance (endpoint, prefixes, label service),
see [[Help:Contributing/query]].
see [[Help:Contributing/query]].
== Running example: dogs and cats ==
'''GROUP BY + COUNT + VALUES''' — how many of each animal are in Wikidata?
<syntaxhighlight lang="sparql">
SELECT ?animal ?animalLabel (COUNT(?item) AS ?count) WHERE {
  VALUES ?animal { wd:Q144 wd:Q146 }        # dog, cat
  ?item wdt:P31 ?animal .                  # ?item is an instance of ?animal
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
GROUP BY ?animal ?animalLabel
</syntaxhighlight>
Result:
<syntaxhighlight lang="text">
dog  553
cat  239
</syntaxhighlight>
This sheet uses that query as its running example: VALUES and GROUP BY in the
first line, the animal classes (wd:Q144 dog, wd:Q146 cat) as VALUES, the
pattern <syntaxhighlight lang="sparql" inline>?item wdt:P31 ?animal</syntaxhighlight>
("is an instance of") as the triple, and COUNT as the aggregate.


== Building a query ==
== Building a query ==


Every query is built from '''triple patterns''': <syntaxhighlight lang="sparql" inline>subject predicate object .</syntaxhighlight>
A query is a list of '''triple patterns''':
A triple states one fact about the data; a query joins several triples to answer a
<syntaxhighlight lang="sparql" inline>subject predicate object .</syntaxhighlight>
question. You usually know two of the three parts and query the third:
You know some parts, query the rest:


{| class="wikitable"
{| class="wikitable"
Line 25: Line 49:
|}
|}


Write the question in this order and the query writes itself:
Write the question in that order and the query writes itself:


<syntaxhighlight lang="sparql">
<syntaxhighlight lang="sparql">
Line 39: Line 63:
</syntaxhighlight>
</syntaxhighlight>


Values can be:
The three kinds of values a triple can hold, each shown in a query:
* '''IRIs''' — entities (wd:Q144), properties (wdt:P31), other resources
 
* '''Literals''' — typed values or language-tagged strings: <syntaxhighlight lang="sparql" inline>"42"^^xsd:integer</syntaxhighlight>, <syntaxhighlight lang="sparql" inline>"2026-08-19"^^xsd:date</syntaxhighlight>, <syntaxhighlight lang="sparql" inline>"dog"@en</syntaxhighlight>, <syntaxhighlight lang="sparql" inline>"chien"@fr</syntaxhighlight>
'''IRI''' — a resource: an entity (wd:Q142), a property (wdt:P1082), or
* '''Blank nodes''' — <syntaxhighlight lang="sparql" inline>[]</syntaxhighlight> or <syntaxhighlight lang="sparql" inline>_:x</syntaxhighlight>: "some unnamed thing", not an IRI
anything else. In the pattern above, France and its population property are
IRIs; the thing we don't know yet is a variable:
 
<syntaxhighlight lang="sparql">
SELECT ?population WHERE {
  wd:Q142 wdt:P1082 ?population .    # IRI  IRI  variable
}
</syntaxhighlight>
 
'''Literal''' — a value, not a resource: a typed number/date, or a string with
a language tag. Dog's English label is the literal <syntaxhighlight lang="sparql" inline>"dog"@en</syntaxhighlight>:
 
<syntaxhighlight lang="sparql">
SELECT ?label WHERE {
  wd:Q144 rdfs:label ?label .
  FILTER(LANG(?label) = "en")
}
</syntaxhighlight>
 
Result:
<syntaxhighlight lang="text">
dog
</syntaxhighlight>
 
Other literals: <syntaxhighlight lang="sparql" inline>"42"^^xsd:integer</syntaxhighlight>,
<syntaxhighlight lang="sparql" inline>"2026-08-19"^^xsd:date</syntaxhighlight>,
<syntaxhighlight lang="sparql" inline>"chien"@fr</syntaxhighlight>.
 
'''Blank node''' — "some unnamed thing", written <syntaxhighlight lang="sparql" inline>[]</syntaxhighlight> or
<syntaxhighlight lang="sparql" inline">_:x</syntaxhighlight>. Use it when a value exists but you don't care
what it is — here, dogs that have an image:
 
<syntaxhighlight lang="sparql">
SELECT ?dogLabel WHERE {
  ?dog wdt:P31/wdt:P279* wd:Q144 .
  ?dog wdt:P18 [] .          # has an image — any image will do
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
LIMIT 3
</syntaxhighlight>
 
Result:
<syntaxhighlight lang="text">
Diamond
Dog of Osu
Endal
</syntaxhighlight>


<blockquote>'''Gotcha:''' blank-node labels (<syntaxhighlight lang="sparql" inline>_:x</syntaxhighlight>) are local to one query — they are not IRIs and cannot be referenced across queries.</blockquote>
<blockquote>'''Gotcha:''' blank-node labels (<syntaxhighlight lang="sparql" inline>_:x</syntaxhighlight>) are local to one query — they are not IRIs and cannot be referenced across queries.</blockquote>
Line 117: Line 187:
== Solution modifiers ==
== Solution modifiers ==


Each modifier shown without / with, side by side.
Each modifier shown without / with, side by side; the highlighted line(s)
show what the modifier adds.


'''DISTINCT''' — drop duplicate rows. Einstein and Obama are both male, so the
'''DISTINCT''' — drop duplicate rows. Einstein and Obama are both male, so the
Line 140: Line 211:
</syntaxhighlight>
</syntaxhighlight>
||
||
<syntaxhighlight lang="sparql">
<syntaxhighlight lang="sparql" line highlight="1">
SELECT DISTINCT ?genderLabel WHERE {
SELECT DISTINCT ?genderLabel WHERE {
   VALUES ?person { wd:Q937 wd:Q76 }
   VALUES ?person { wd:Q937 wd:Q76 }
Line 153: Line 224:
</syntaxhighlight>
</syntaxhighlight>
|}
|}
Diff:
<syntaxhighlight lang="diff">
SELECT ?genderLabel WHERE {
  VALUES ?person { wd:Q937 wd:Q76 }
  ?person wdt:P21 ?gender .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
+DISTINCT
</syntaxhighlight>


'''ORDER BY + LIMIT''' — the 3 most populous countries, sorted descending:
'''ORDER BY + LIMIT''' — the 3 most populous countries, sorted descending:
Line 185: Line 246:
</syntaxhighlight>
</syntaxhighlight>
||
||
<syntaxhighlight lang="sparql">
<syntaxhighlight lang="sparql" line highlight="6">
SELECT ?countryLabel ?population WHERE {
SELECT ?countryLabel ?population WHERE {
   VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
   VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
Line 201: Line 262:
</syntaxhighlight>
</syntaxhighlight>
|}
|}
Diff:
<syntaxhighlight lang="diff">
SELECT ?countryLabel ?population WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
+ORDER BY DESC(?population)
</syntaxhighlight>


'''LIMIT''' — at most n rows:
'''LIMIT''' — at most n rows:
Line 233: Line 284:
</syntaxhighlight>
</syntaxhighlight>
||
||
<syntaxhighlight lang="sparql">
<syntaxhighlight lang="sparql" line highlight="6">
SELECT ?countryLabel WHERE {
SELECT ?countryLabel WHERE {
   VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
   VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
Line 248: Line 299:
</syntaxhighlight>
</syntaxhighlight>
|}
|}
Diff:
<syntaxhighlight lang="diff">
SELECT ?countryLabel WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
+LIMIT 2
</syntaxhighlight>


'''OFFSET''' — skip rows (paging). The 2nd most populous country:
'''OFFSET''' — skip rows (paging). The 2nd most populous country:
Line 280: Line 321:
</syntaxhighlight>
</syntaxhighlight>
||
||
<syntaxhighlight lang="sparql">
<syntaxhighlight lang="sparql" line highlight="7">
SELECT ?countryLabel ?population WHERE {
SELECT ?countryLabel ?population WHERE {
   ?country wdt:P31 wd:Q6256 .
   ?country wdt:P31 wd:Q6256 .
Line 295: Line 336:
</syntaxhighlight>
</syntaxhighlight>
|}
|}
Diff:
<syntaxhighlight lang="diff">
SELECT ?countryLabel ?population WHERE {
  ?country wdt:P31 wd:Q6256 .
  ?country wdt:P1082 ?population .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
ORDER BY DESC(?population)
LIMIT 1
+OFFSET 1
</syntaxhighlight>


'''GROUP BY''' — covered with aggregation (see Aggregates).
'''GROUP BY''' — covered with aggregation (see Aggregates).
Line 443: Line 472:
Albert Einstein  1879
Albert Einstein  1879
Barack Obama    1961
Barack Obama    1961
</syntaxhighlight>
== Running example: dogs and cats ==
'''GROUP BY + COUNT + VALUES''' — how many of each animal are in Wikidata?
<syntaxhighlight lang="sparql">
SELECT ?animal ?animalLabel (COUNT(?item) AS ?count) WHERE {
  VALUES ?animal { wd:Q144 wd:Q146 }        # dog, cat
  ?item wdt:P31 ?animal .                  # ?item is an instance of ?animal
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
GROUP BY ?animal ?animalLabel
</syntaxhighlight>
Result:
<syntaxhighlight lang="text">
dog  553
cat  239
</syntaxhighlight>
</syntaxhighlight>


Line 574: Line 584:
== Aggregates ==
== Aggregates ==


COUNT, SUM, AVG, MIN, MAX, SAMPLE (pick one arbitrary value), GROUP_CONCAT.
Aggregates collapse many rows into one per group. All examples use the same
three countries (China, US, India).
 
'''COUNT''' — how many values (the running example counts instances per
animal; here: values of <syntaxhighlight lang="sparql" inline>wdt:P1082</syntaxhighlight> for the three countries):
 
<syntaxhighlight lang="sparql">
SELECT (COUNT(?population) AS ?n) WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
}
</syntaxhighlight>
 
Result:
<syntaxhighlight lang="text">
3
</syntaxhighlight>
 
'''SUM''' — combined population of the three:
 
<syntaxhighlight lang="sparql">
SELECT (SUM(?population) AS ?total) WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
}
</syntaxhighlight>
 
Result:
<syntaxhighlight lang="text">
3071094235
</syntaxhighlight>
 
'''AVG''' — mean population of the three:
 
<syntaxhighlight lang="sparql">
SELECT (AVG(?population) AS ?avg) WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
}
</syntaxhighlight>
 
Result:
<syntaxhighlight lang="text">
1023698078.33
</syntaxhighlight>
 
'''MIN / MAX''' — smallest and largest of the three:
 
<syntaxhighlight lang="sparql">
SELECT (MIN(?population) AS ?min) (MAX(?population) AS ?max) WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
}
</syntaxhighlight>
 
Result:
<syntaxhighlight lang="text">
340110988  1404890000
</syntaxhighlight>


'''HAVING''' — species with more than 400 direct instances (the running example,
'''SAMPLE''' — one arbitrary value (useful to squash duplicates):
filtered):


<syntaxhighlight lang="sparql">
<syntaxhighlight lang="sparql">
SELECT ?animalLabel (COUNT(?item) AS ?n) WHERE {
SELECT (SAMPLE(?countryLabel) AS ?anyCountry) WHERE {
   VALUES ?animal { wd:Q144 wd:Q146 }
   VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
   ?item wdt:P31 ?animal .
   ?country wdt:P1082 ?population .
   SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
   ?country rdfs:label ?countryLabel .
  FILTER(LANG(?countryLabel) = "en")
}
}
GROUP BY ?animal ?animalLabel
HAVING (COUNT(?item) > 400)
</syntaxhighlight>
</syntaxhighlight>


Result:
Result:
<syntaxhighlight lang="text">
<syntaxhighlight lang="text">
dog  553
United States
</syntaxhighlight>
</syntaxhighlight>


Line 608: Line 674:
<syntaxhighlight lang="text">
<syntaxhighlight lang="text">
Albert Einstein  Nobel Prize in Physics, …
Albert Einstein  Nobel Prize in Physics, …
</syntaxhighlight>
'''GROUP BY + HAVING''' — the running example, filtered to groups with more
than 400 instances:
<syntaxhighlight lang="sparql">
SELECT ?animalLabel (COUNT(?item) AS ?n) WHERE {
  VALUES ?animal { wd:Q144 wd:Q146 }
  ?item wdt:P31 ?animal .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
GROUP BY ?animal ?animalLabel
HAVING (COUNT(?item) > 400)
</syntaxhighlight>
Result:
<syntaxhighlight lang="text">
dog  553
</syntaxhighlight>
</syntaxhighlight>



Revision as of 12:33, 19 August 2026

Languages: English · français · Esperanto

Quick reference for smart people — part of our dev cheatsheets collection.

SPARQL 1.1 quick syntax reference — for people who already know what SPARQL is and need reminders on syntax. All examples run as-is against the public Wikidata endpoint https://query.wikidata.org/sparql. For a proper tutorial, take the Wikidata SPARQL tutorial. For querying a different Wikibase instance (endpoint, prefixes, label service), see Help:Contributing/query.

Running example: dogs and cats

GROUP BY + COUNT + VALUES — how many of each animal are in Wikidata?

SELECT ?animal ?animalLabel (COUNT(?item) AS ?count) WHERE {
  VALUES ?animal { wd:Q144 wd:Q146 }        # dog, cat
  ?item wdt:P31 ?animal .                   # ?item is an instance of ?animal
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
GROUP BY ?animal ?animalLabel

Result:

dog  553
cat  239

This sheet uses that query as its running example: VALUES and GROUP BY in the first line, the animal classes (wd:Q144 dog, wd:Q146 cat) as VALUES, the pattern ?item wdt:P31 ?animal ("is an instance of") as the triple, and COUNT as the aggregate.

Building a query

A query is a list of triple patterns: subject predicate object . You know some parts, query the rest:

Question Known parts Pattern
"What is the population of France?" subject France (wd:Q142) + predicate population (wdt:P1082) wd:Q142 wdt:P1082 ?population .
"Which things are dogs?" predicate instance-of (wdt:P31) + object dog (wd:Q144) ?x wdt:P31 wd:Q144 .
"What is known about Einstein?" subject Einstein (wd:Q937) wd:Q937 ?predicate ?value .

Write the question in that order and the query writes itself:

# "What is the population of France?"
SELECT ?population WHERE {
  wd:Q142 wdt:P1082 ?population .
}

Result:

68605616

The three kinds of values a triple can hold, each shown in a query:

IRI — a resource: an entity (wd:Q142), a property (wdt:P1082), or anything else. In the pattern above, France and its population property are IRIs; the thing we don't know yet is a variable:

SELECT ?population WHERE {
  wd:Q142 wdt:P1082 ?population .    # IRI  IRI  variable
}

Literal — a value, not a resource: a typed number/date, or a string with a language tag. Dog's English label is the literal "dog"@en:

SELECT ?label WHERE {
  wd:Q144 rdfs:label ?label .
  FILTER(LANG(?label) = "en")
}

Result:

dog

Other literals: "42"^^xsd:integer, "2026-08-19"^^xsd:date, "chien"@fr.

Blank node — "some unnamed thing", written [] or

_:x

. Use it when a value exists but you don't care

what it is — here, dogs that have an image:

SELECT ?dogLabel WHERE {
  ?dog wdt:P31/wdt:P279* wd:Q144 .
  ?dog wdt:P18 [] .          # has an image — any image will do
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
LIMIT 3

Result:

Diamond
Dog of Osu
Endal

Gotcha: blank-node labels (_:x) are local to one query — they are not IRIs and cannot be referenced across queries.

Gotcha: the prefixes wd:/wdt: are Wikidata's; other instances define their own (see Help:Contributing/query).

Query forms

Form Returns Use when
SELECT table of variable bindings you want rows of data
ASK true/false you only need to know whether something exists
CONSTRUCT an RDF graph (triples) you want the result as RDF, not a table
DESCRIBE a graph describing the resource you want everything known about an entity

SELECT — what is the population of France?

SELECT ?population WHERE {
  wd:Q142 wdt:P1082 ?population .
}

Result:

68605616

ASK — is there at least one dog in Wikidata?

ASK WHERE { ?x wdt:P31 wd:Q144 . }

Result:

true

CONSTRUCT — every dog as RDF (first two). Each result row becomes a triple ?x wdt:P31 wd:Q144:

CONSTRUCT { ?x wdt:P31 wd:Q144 . }
WHERE { ?x wdt:P31 wd:Q144 . } LIMIT 2

Result (visualised, N-Triples style):

Q186486  wdt:P31  wd:Q144
Q280571  wdt:P31  wd:Q144

DESCRIBE — everything known about Einstein (all triples with wd:Q937 as subject or object):

DESCRIBE wd:Q937

Result (visualised, N-Triples style, first few of thousands):

Q937  rdfs:label   "Albert Einstein"@en
Q937  wdt:P569     1879-03-14
Q937  wdt:P570     1955-04-18
Q937  wdt:P21      wd:Q6581097   # male

Solution modifiers

Each modifier shown without / with, side by side; the highlighted line(s) show what the modifier adds.

DISTINCT — drop duplicate rows. Einstein and Obama are both male, so the gender repeats:

Without With DISTINCT
SELECT ?genderLabel WHERE {
  VALUES ?person { wd:Q937 wd:Q76 }
  ?person wdt:P21 ?gender .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Result:

male
male
SELECT DISTINCT ?genderLabel WHERE {
  VALUES ?person { wd:Q937 wd:Q76 }
  ?person wdt:P21 ?gender .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Result:

male

ORDER BY + LIMIT — the 3 most populous countries, sorted descending:

Without (arbitrary order) With ORDER BY DESC + LIMIT
SELECT ?countryLabel ?population WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }   # China, US, India
  ?country wdt:P1082 ?population .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Result:

United States        340110988
China               1404890000
India               1326093247
SELECT ?countryLabel ?population WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
ORDER BY DESC(?population)

Result:

China               1404890000
India               1326093247
United States        340110988

LIMIT — at most n rows:

Without (all 3) With LIMIT 2
SELECT ?countryLabel WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Result:

United States
China
India
SELECT ?countryLabel WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
LIMIT 2

Result:

United States
China

OFFSET — skip rows (paging). The 2nd most populous country:

With LIMIT 1 (first) With LIMIT 1 OFFSET 1 (second)
SELECT ?countryLabel ?population WHERE {
  ?country wdt:P31 wd:Q6256 .
  ?country wdt:P1082 ?population .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
ORDER BY DESC(?population)
LIMIT 1

Result:

China  1404890000
SELECT ?countryLabel ?population WHERE {
  ?country wdt:P31 wd:Q6256 .
  ?country wdt:P1082 ?population .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
ORDER BY DESC(?population)
LIMIT 1 OFFSET 1

Result:

India  1326093247

GROUP BY — covered with aggregation (see Aggregates).

FILTER

Category Operators / functions
comparison = < > <= >= !=
logical && || !
string STR() CONTAINS() STRSTARTS() STRENDS() REGEX()
numeric ABS() ROUND() FLOOR() CEIL()
date/time YEAR() MONTH() DAY() NOW()
term tests isIRI() isBlank() isLiteral() LANG() DATATYPE()

comparison — countries with more than 1 billion people:

SELECT ?countryLabel ?population WHERE {
  ?country wdt:P31 wd:Q6256 .
  ?country wdt:P1082 ?population .
  FILTER(?population > 1000000000)
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Result:

China   1404890000
India   1326093247

logical (AND) — countries with 300M–500M people:

SELECT ?countryLabel ?population WHERE {
  ?country wdt:P31 wd:Q6256 .
  ?country wdt:P1082 ?population .
  FILTER(?population > 300000000 && ?population < 500000000)
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Result:

United States  340110988

string (STRSTARTS) — countries whose English label starts with "S":

SELECT ?countryLabel WHERE {
  ?country wdt:P31 wd:Q6256 .
  ?country rdfs:label ?countryLabel .
  FILTER(LANG(?countryLabel) = "en" && STRSTARTS(?countryLabel, "S"))
}
LIMIT 3

Result:

Saint Kitts and Nevis
Somaliland
Saint Vincent and the Grenadines

numeric (ROUND) — France's population in millions, rounded:

SELECT ?millions (ROUND(?millions) AS ?rounded) WHERE {
  wd:Q142 wdt:P1082 ?population .
  BIND(?population / 1000000 AS ?millions)
}

Result:

68.605616  69

date/time (YEAR) — Einstein's birth year:

SELECT ?personLabel (YEAR(?birth) AS ?year) WHERE {
  wd:Q937 wdt:P569 ?birth .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Result:

Albert Einstein  1879

term test (isIRI) — the values of wdt:P31 on a dog are entities (IRIs), not literals:

SELECT ?o WHERE {
  wd:Q144 wdt:P31 ?o .
  FILTER(isIRI(?o))
}

Result:

http://www.wikidata.org/entity/Q55983715
http://www.wikidata.org/entity/Q136772238

Gotcha: an unbound variable in a FILTER makes the row fail (unbound ≠ false) — guard with BOUND() or restructure with OPTIONAL.

VALUES & BIND

VALUES restricts a variable to a list; BIND computes a new variable. Together: birth years of two people, computed, not looked up:

SELECT ?personLabel ?birthYear WHERE {
  VALUES ?person { wd:Q937 wd:Q76 }        # Einstein, Obama
  ?person wdt:P569 ?birth .
  BIND(YEAR(?birth) AS ?birthYear)
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Result:

Albert Einstein  1879
Barack Obama     1961

OPTIONAL, UNION, MINUS

Keyword Meaning
OPTIONAL left join: keep the row, leave the variable unbound when absent
UNION alternatives (the default between patterns is AND, not OR)
MINUS remove rows that match the pattern

OPTIONAL — Einstein (died 1955) vs Obama (alive); ?deathLabel is unbound for Obama:

SELECT ?personLabel ?deathLabel WHERE {
  VALUES ?person { wd:Q937 wd:Q76 }         # Einstein, Barack Obama
  OPTIONAL { ?person wdt:P570 ?death . }
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Result:

Albert Einstein  1955-04-18
Barack Obama     (unbound)

MINUS — Nobel laureates minus the French ones:

SELECT ?personLabel WHERE {
  ?person wdt:P166 wd:Q7191 .
  MINUS { ?person wdt:P27 wd:Q142 . }
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
LIMIT 3

Result:

Nobel Prize winner
Adam Bernau
Santiago Carril

UNION — dogs AND cats in one result set:

SELECT ?animalLabel (COUNT(?item) AS ?n) WHERE {
  { ?item wdt:P31 wd:Q144 . BIND("dog" AS ?animalLabel) }
  UNION
  { ?item wdt:P31 wd:Q146 . BIND("cat" AS ?animalLabel) }
}
GROUP BY ?animalLabel

Result:

dog  553
cat  239

Gotcha: the default between triple patterns is AND (join) — use UNION for alternatives.

Gotcha: FILTER NOT EXISTS differs from MINUS when variables are unbound — prefer MINUS for set-difference semantics.

Property paths

Path Meaning
wdt:P40/wdt:P40 two hops (sequence)
wdt:P40+ one or more hops
wdt:P40* zero or more hops
wdt:P40? zero or one hop
wdt:P41 either property
^wdt:P40 inverse direction
!wdt:P40 any property except P40

wdt:P31/wdt:P279* — named dogs, including breeds and other subclasses ("instance of something that is a dog or a subclass of dog"):

SELECT ?thing ?thingLabel WHERE {
  ?thing wdt:P31/wdt:P279* wd:Q144 .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
LIMIT 3

Result:

Theo
Tich
Tickle Em Jock

Gotcha: variables used only inside a property path (e.g. ?s wdt:P40/wdt:P40 ?o) cannot be selected.

Aggregates

Aggregates collapse many rows into one per group. All examples use the same three countries (China, US, India).

COUNT — how many values (the running example counts instances per animal; here: values of wdt:P1082 for the three countries):

SELECT (COUNT(?population) AS ?n) WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
}

Result:

3

SUM — combined population of the three:

SELECT (SUM(?population) AS ?total) WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
}

Result:

3071094235

AVG — mean population of the three:

SELECT (AVG(?population) AS ?avg) WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
}

Result:

1023698078.33

MIN / MAX — smallest and largest of the three:

SELECT (MIN(?population) AS ?min) (MAX(?population) AS ?max) WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
}

Result:

340110988  1404890000

SAMPLE — one arbitrary value (useful to squash duplicates):

SELECT (SAMPLE(?countryLabel) AS ?anyCountry) WHERE {
  VALUES ?country { wd:Q148 wd:Q30 wd:Q668 }
  ?country wdt:P1082 ?population .
  ?country rdfs:label ?countryLabel .
  FILTER(LANG(?countryLabel) = "en")
}

Result:

United States

GROUP_CONCAT — Einstein's awards in one cell:

SELECT ?personLabel (GROUP_CONCAT(?awardLabel; SEPARATOR=", ") AS ?awards) WHERE {
  VALUES ?person { wd:Q937 }
  ?person wdt:P166 ?award .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
GROUP BY ?personLabel

Result:

Albert Einstein  Nobel Prize in Physics, …

GROUP BY + HAVING — the running example, filtered to groups with more than 400 instances:

SELECT ?animalLabel (COUNT(?item) AS ?n) WHERE {
  VALUES ?animal { wd:Q144 wd:Q146 }
  ?item wdt:P31 ?animal .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
GROUP BY ?animal ?animalLabel
HAVING (COUNT(?item) > 400)

Result:

dog  553

Gotcha: aggregates need GROUP BY for every non-aggregated variable; forgetting one mixes unrelated rows.

Subqueries

A query inside a query — useful for "the X with the max Y" patterns.

The most populous country, computed via a subquery:

SELECT ?countryLabel ?max WHERE {
  {
    SELECT (MAX(?population) AS ?max) WHERE {
      ?c wdt:P31 wd:Q6256 .
      ?c wdt:P1082 ?population .
    }
  }
  ?country wdt:P31 wd:Q6256 .
  ?country wdt:P1082 ?max .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

Result:

China  1404890000

SERVICE (labels, federation)

The label service turns entity IDs into human-readable labels — used in most queries above:

SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
# then reference ?xLabel for every ?x in the query
# Federating to another endpoint (needs the remote's own IRIs, e.g. via owl:sameAs)
SELECT ?cityLabel WHERE {
  wd:Q64 wdt:P36 ?city .
  ?city owl:sameAs ?dbpediaCity .
  SERVICE <https://dbpedia.org/sparql> {
    ?dbpediaCity rdfs:label ?cityLabel .
    FILTER(LANG(?cityLabel) = "en")
  }
}

Further reading