UNION clause

The UNION clause is used to combine the result of multiple queries.

Combine queries and retain duplicates
Combine queries and remove duplicates

Data Set

The following examples are executed with this data set. You can create this data set locally by executing the queries at the end of the page: Data Set.

1. Combine queries and retain duplicates

To combine two or more queries and return their results without removing duplicates, use the UNION ALL clause. First, let's add a few existing nodes to the data set.

CREATE (:Person { name: 'John' });
CREATE (:Person { name: 'Anna' });

A query with the UNION ALL clause could look like this:

MATCH (c:Country) 
RETURN c.name as columnName
UNION ALL 
MATCH (p:Person)
RETURN p.name AS columnName;

Output:

+----------------+
| columnName     |
+----------------+
| Germany        |
| France         |
| United Kingdom |
| John           |
| Harry          |
| Anna           |
| John           |
| Anna           |
+----------------+

2. Combine queries and remove duplicates

To combine two or more queries and return their results without removing duplicates, use the UNION clause without ALL.

MATCH (c:Country) 
RETURN c.name as columnName
UNION 
MATCH (p:Person)
RETURN p.name AS columnName;

Output:

+----------------+
| columnName     |
+----------------+
| Germany        |
| France         |
| United Kingdom |
| John           |
| Harry          |
| Anna           |
+----------------+

Data set Queries

We encourage you to try out the examples by yourself. You can get our data set locally by executing the following query block.

MATCH (n) DETACH DELETE n;

CREATE (c1:Country { name: 'Germany', language: 'German', continent: 'Europe', population: 83000000 });
CREATE (c2:Country { name: 'France', language: 'French', continent: 'Europe', population: 67000000 });
CREATE (c3:Country { name: 'United Kingdom', language: 'English', continent: 'Europe', population: 66000000 });

MATCH (c1),(c2)
WHERE c1.name= 'Germany' AND c2.name = 'France'
CREATE (c2)<-[:WORKING_IN { date_of_start: 2014 }]-(p:Person { name: 'John' })-[:LIVING_IN { date_of_start: 2014 }]->(c1);

MATCH (c)
WHERE c.name= 'United Kingdom'
CREATE (c)<-[:WORKING_IN { date_of_start: 2014 }]-(p:Person { name: 'Harry' })-[:LIVING_IN { date_of_start: 2013 }]->(c);

MATCH (p1),(p2)
WHERE p1.name = 'John' AND p2.name = 'Harry'
CREATE (p1)-[:FRIENDS_WITH { date_of_start: 2011 }]->(p2);

MATCH (p1),(p2)
WHERE p1.name = 'John' AND p2.name = 'Harry'
CREATE (p1)<-[:FRIENDS_WITH { date_of_start: 2012 }]-(:Person { name: 'Anna' })-[:FRIENDS_WITH { date_of_start: 2014 }]->(p2);

MATCH (p),(c1),(c2)
WHERE p.name = 'Anna' AND c1.name = 'United Kingdom' AND c2.name = 'Germany'
CREATE (c2)<-[:LIVING_IN { date_of_start: 2014 }]-(p)-[:LIVING_IN { date_of_start: 2014 }]->(c1);

CREATE (:Person { name: 'John' });
CREATE (:Person { name: 'Anna' });

MATCH (n)-[r]->(m) RETURN n,r,m;