GROUP_CONCAT - SPARQLqueries

Understanding GROUP_CONCAT

GROUP_CONCAT is an aggregate function that joins multiple values into a single delimited string. It's useful when you want to see all related items in one row rather than multiple rows.

Syntax	Description
`GROUP_CONCAT(?var)`	Concatenate with space separator
`GROUP_CONCAT(?var; SEPARATOR=", ")`	Concatenate with custom separator
`GROUP_CONCAT(DISTINCT ?var)`	Concatenate unique values only

Basic GROUP_CONCAT Examples

Country Official Languages

Run ↗

SELECT ?country ?countryLabel (GROUP_CONCAT(DISTINCT ?langLabel; SEPARATOR=", ") AS ?languages)
WHERE {
  VALUES ?country { wd:Q39 wd:Q31 wd:Q183 wd:Q16 }
  ?country wdt:P37 ?lang .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". ?lang rdfs:label ?langLabel. ?country rdfs:label ?countryLabel. }
}
GROUP BY ?country ?countryLabel

Aggregate List all official languages per country

This query lists the official languages of four multilingual countries: Switzerland (Q39), Belgium (Q31), Germany (Q183), and Canada (Q16). GROUP_CONCAT combines all languages into a comma-separated list for each country.

Author's Occupations

Run ↗

SELECT ?person ?personLabel (GROUP_CONCAT(DISTINCT ?occLabel; SEPARATOR=", ") AS ?occupations)
WHERE {
  VALUES ?person { wd:Q5879 wd:Q692 wd:Q7836 wd:Q1394 }
  ?person wdt:P106 ?occ .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". ?occ rdfs:label ?occLabel. ?person rdfs:label ?personLabel. }
}
GROUP BY ?person ?personLabel

Aggregate All occupations for famous thinkers

Historical figures often had multiple occupations. This query shows all occupations for Goethe (Q5879), Shakespeare (Q692), Nietzsche (Q7836), and Voltaire (Q1394) in a single comma-separated list per person.

Different Separators

Borders with Semicolon Separator

Run ↗

SELECT ?country ?countryLabel (GROUP_CONCAT(DISTINCT ?borderLabel; SEPARATOR="; ") AS ?borders)
WHERE {
  VALUES ?country { wd:Q183 wd:Q142 wd:Q38 }
  ?country wdt:P47 ?border .
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". ?border rdfs:label ?borderLabel. ?country rdfs:label ?countryLabel. }
}
GROUP BY ?country ?countryLabel

Aggregate Countries sharing borders, semicolon-separated

The SEPARATOR parameter allows any string delimiter. This example uses semicolons to list all countries that share borders with Germany (Q183), France (Q142), and Italy (Q38).

GROUP_CONCAT with COUNT

Countries with Their Cities

Run ↗

SELECT ?country ?countryLabel (COUNT(?city) AS ?cityCount)
  (GROUP_CONCAT(DISTINCT ?cityLabel; SEPARATOR=", ") AS ?cities)
WHERE {
  VALUES ?country { wd:Q347 wd:Q574 wd:Q414 }
  ?city wdt:P31 wd:Q515 ;
        wdt:P17 ?country ;
        wdt:P1082 ?pop .
  FILTER(?pop > 100000)
  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". ?city rdfs:label ?cityLabel. ?country rdfs:label ?countryLabel. }
}
GROUP BY ?country ?countryLabel
ORDER BY DESC(?cityCount)

Aggregate Count and list large cities per country

Combining COUNT and GROUP_CONCAT lets you see both how many items exist and what they are. This query shows cities with over 100,000 people in Liechtenstein (Q347), East Timor (Q574), and Argentina (Q414).

Key Entities Used in Examples

Entity	Description
`wd:Q39`	Switzerland
`wd:Q31`	Belgium
`wd:Q183`	Germany
`wd:Q16`	Canada
`wd:Q515`	City
`wdt:P37`	Official language
`wdt:P47`	Shares border with
`wdt:P106`	Occupation
`wdt:P17`	Country
`wdt:P1082`	Population