Operators

This page contains an overview of the available Cypher® operators.

Operators at a glance

Aggregation operators

DISTINCT

Property operators

. for static property access, [] for dynamic property access, = for replacing all properties, += for mutating specific properties

Map operators

. for static value access by key, [] for dynamic value access by key

Aggregation operators

The aggregation operators comprise:

  • remove duplicates values: DISTINCT

Using the DISTINCT operator

Retrieve the unique eye colors from Person nodes.

Query
CREATE
  (a:Person {name: 'Anne', eyeColor: 'blue'}),
  (b:Person {name: 'Bill', eyeColor: 'brown'}),
  (c:Person {name: 'Carol', eyeColor: 'blue'})
WITH [a, b, c] AS ps
UNWIND ps AS p
RETURN DISTINCT p.eyeColor

Even though both 'Anne' and 'Carol' have blue eyes, 'blue' is only returned once.

Table 1. Result
p.eyeColor

"blue"

"brown"

Rows: 2

DISTINCT is commonly used in conjunction with aggregating functions.

Property operators

The property operators pertain to a node or a relationship, and comprise:

  • statically access the property of a node or relationship using the dot operator: .

  • dynamically access the property of a node or relationship using the subscript operator: []

  • property replacement = for replacing all properties of a node or relationship

  • property mutation operator += for setting specific properties of a node or relationship

Statically accessing a property of a node or relationship using the . operator

Query
CREATE
  (a:Person {name: 'Jane', livesIn: 'London'}),
  (b:Person {name: 'Tom', livesIn: 'Copenhagen'})
WITH a, b
MATCH (p:Person)
RETURN  p.name
Table 2. Result
p.name

"Jane"

"Tom"

Rows: 2

Filtering on a dynamically-computed property key using the [] operator

Query
CREATE
  (a:Restaurant {name: 'Hungry Jo', rating_hygiene: 10, rating_food: 7}),
  (b:Restaurant {name: 'Buttercup Tea Rooms', rating_hygiene: 5, rating_food: 6}),
  (c1:Category {name: 'hygiene'}),
  (c2:Category {name: 'food'})
WITH a, b, c1, c2
MATCH (restaurant:Restaurant), (category:Category)
WHERE restaurant["rating_" + category.name] > 6
RETURN DISTINCT restaurant.name
Table 3. Result
restaurant.name

"Hungry Jo"

Rows: 1

See also WHERE → Filter on dynamic properties.

The behavior of the [] operator with respect to null is detailed here.

Replacing all properties of a node or relationship using the = operator

Query
CREATE (a:Person {name: 'Sofia', age: 20})
WITH a
MATCH (p:Person {name: 'Sofia'})
SET p = {name: 'Ellen', livesIn: 'London'}
RETURN p.name, p.age, p.livesIn

All the existing properties on the node are replaced by those provided in the map; i.e. the name property is updated from Sofia to Ellen, the age property is deleted, and the livesIn property is added.

Table 4. Result
p.name p.age p.livesIn

"Ellen"

<null>

"London"

Rows: 1

See Replace all properties using a map and = for more details on using the property replacement operator =.

Mutating specific properties of a node or relationship using the += operator

Query
CREATE (a:Person {name: 'Sofia', age: 20})
WITH a
MATCH (p:Person {name: 'Sofia'})
SET p += {name: 'Ellen', livesIn: 'London'}
RETURN p.name, p.age, p.livesIn

The properties on the node are updated as follows by those provided in the map: the name property is updated from Sofia to Ellen, the age property is left untouched, and the livesIn property is added.

Table 5. Result
p.name p.age p.livesIn

"Ellen"

20

"London"

Rows: 1

See xref::clauses/set.adoc#set-setting-properties-using-map[Mutate specific properties using a map and =`] for more details on using the property mutation operator `=.

Map operators

The map operators comprise:

  • statically access the value of a map by key using the dot operator: .

  • dynamically access the value of a map by key using the subscript operator: []

The behavior of the [] operator with respect to null is detailed in the working with null page.

Statically accessing the value of a nested map by key using the . operator

Query
WITH {person: {name: 'Anne', age: 25}} AS p
RETURN  p.person.name
Table 6. Result
p.person.name

"Anne"

Rows: 1

Dynamically accessing the value of a map by key using the [] operator and a parameter

A parameter may be used to specify the key of the value to access:

Parameters
{
  "myKey" : "name"
}
Query
WITH {name: 'Anne', age: 25} AS a
RETURN a[$myKey] AS result
Table 7. Result
result

"Anne"

Rows: 1

More information can be found in the Maps chapter.