3.2.5. Operators

3.2.5.1. Operators at a glance

General operators

DISTINCT, . for property access, [] for dynamic property access

Mathematical operators

+, -, *, /, %, ^

Comparison operators

=, <>, <, >, , >=, IS NULL, IS NOT NULL

String-specific comparison operators

STARTS WITH, ENDS WITH, CONTAINS

Boolean operators

AND, OR, XOR, NOT

String operators

+ for concatenation, =~ for regex matching

List operators

+ for concatenation, IN to check existence of an element in a list, [] for accessing element(s)

3.2.5.2. General operators

The general operators comprise:

  • remove duplicates values: DISTINCT
  • access the property of a node, relationship or literal map: .
  • dynamic property access: []
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
MATCH (p:Person)
RETURN DISTINCT p.eyeColor

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

Result. 

+------------+
| p.eyeColor |
+------------+
| "blue"     |
| "brown"    |
+------------+
2 rows
Nodes created: 3
Properties set: 6
Labels added: 3

DISTINCT is commonly used in conjunction with aggregating functions.

Accessing the property of a nested literal map

Query. 

WITH { person: { name: 'Anne', age: 25 }} AS p
RETURN p.person.name

Result. 

+---------------+
| p.person.name |
+---------------+
| "Anne"        |
+---------------+
1 row

Filtering on a dynamically-computed property key

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

Result. 

+-----------------+
| restaurant.name |
+-----------------+
| "Hungry Jo"     |
+-----------------+
1 row
Nodes created: 4
Properties set: 8
Labels added: 4

See Section 3.3.3.1, “Basic usage” for more details on dynamic property access.

3.2.5.3. Mathematical operators

The mathematical operators comprise:

  • addition: +
  • subtraction or unary minus: -
  • multiplication: *
  • division: /
  • modulo division: %
  • exponentiation: ^
Using the exponentiation operator

Query. 

WITH 2 AS number, 3 AS exponent
RETURN number ^ exponent AS result

Result. 

+--------+
| result |
+--------+
| 8.0    |
+--------+
1 row

Using the unary minus operator

Query. 

WITH -3 AS a, 4 AS b
RETURN b - a AS result

Result. 

+--------+
| result |
+--------+
| 7      |
+--------+
1 row

3.2.5.4. Comparison operators

The comparison operators comprise:

  • equality: =
  • inequality: <>
  • less than: <
  • greater than: >
  • less than or equal to: <=
  • greater than or equal to: >=
  • IS NULL
  • IS NOT NULL

String-specific comparison operators comprise:

  • STARTS WITH: perform case-sensitive prefix searching on strings
  • ENDS WITH: perform case-sensitive suffix searching on strings
  • CONTAINS: perform case-sensitive inclusion searching in strings
Comparing two numbers

Query. 

WITH 4 AS one, 3 AS two
RETURN one > two AS result

Result. 

+--------+
| result |
+--------+
| true   |
+--------+
1 row

See Section 3.2.5.9, “Equality and comparison of values” for more details on the behavior of comparison operators, and Section 3.3.3.7, “Using ranges” for more examples showing how these may be used.

Using STARTS WITH to filter names

Query. 

WITH ['John', 'Mark', 'Jonathan', 'Bill'] AS somenames
UNWIND somenames AS names
WITH names AS candidate
WHERE candidate STARTS WITH 'Jo'
RETURN candidate

Result. 

+------------+
| candidate  |
+------------+
| "John"     |
| "Jonathan" |
+------------+
2 rows

Section 3.3.3.2, “String matching” contains more information regarding the string-specific comparison operators as well as additional examples illustrating the usage thereof.

3.2.5.5. Boolean operators

The boolean operators — also known as logical operators — comprise:

  • conjunction: AND
  • disjunction: OR,
  • exclusive disjunction: XOR
  • negation: NOT

Here is the truth table for AND, OR, XOR and NOT.

a b a AND b a OR b a XOR b NOT a

false

false

false

false

false

true

false

null

false

null

null

true

false

true

false

true

true

true

true

false

false

true

true

false

true

null

null

true

null

false

true

true

true

true

false

false

null

false

false

null

null

null

null

null

null

null

null

null

null

true

null

true

null

null

Using boolean operators to filter numbers

Query. 

WITH [2, 4, 7, 9, 12] AS numberlist
UNWIND numberlist AS number
WITH number
WHERE number = 4 OR (number > 6 AND number < 10)
RETURN number

Result. 

+--------+
| number |
+--------+
| 4      |
| 7      |
| 9      |
+--------+
3 rows

3.2.5.6. String operators

String operators comprise:

  • concatenating strings: +
  • matching a regular expression: =~
Using a regular expression to filter words

Query. 

WITH ['mouse', 'chair', 'door', 'house'] AS wordlist
UNWIND wordlist AS word
WITH word
WHERE word =~ '.*ous.*'
RETURN word

Result. 

+---------+
| word    |
+---------+
| "mouse" |
| "house" |
+---------+
2 rows

Further information and examples regarding the use of regular expressions in filtering can be found in Section 3.3.3.3, “Regular expressions”. In addition, refer to Section 3.2.5.4, “Comparison operators” for details on string-specific comparison operators.

3.2.5.7. List operators

List operators comprise:

  • concatenating lists: +
  • checking if an element exists in a list: IN
  • accessing an element(s) in a list: []
Concatenating two lists

Query. 

RETURN [1,2,3,4,5]+[6,7] AS myList

Result. 

+-----------------+
| myList          |
+-----------------+
| [1,2,3,4,5,6,7] |
+-----------------+
1 row

Using IN to check if a number is in a list

Query. 

WITH [2, 3, 4, 5] AS numberlist
UNWIND numberlist AS number
WITH number
WHERE number IN [2, 3, 8]
RETURN number

Result. 

+--------+
| number |
+--------+
| 2      |
| 3      |
+--------+
2 rows

Accessing elements in a list

Query. 

WITH ['Anne', 'John', 'Bill', 'Diane', 'Eve'] AS names
RETURN names[1..3] AS result

The square brackets will extract the elements from the start index 1, and up to (but excluding) the end index 3.

Result. 

+-----------------+
| result          |
+-----------------+
| ["John","Bill"] |
+-----------------+
1 row

More details on lists can be found in Section 3.2.8.1, “Lists in general”.

3.2.5.8. Property operators

Since version 2.0, the previously supported property operators ? and ! have been removed. This syntax is no longer supported. Missing properties are now returned as null. Please use (NOT(has(<ident>.prop)) OR <ident>.prop=<value>) if you really need the old behavior of the ? operator. — Also, the use of ? for optional relationships has been removed in favor of the newly-introduced OPTIONAL MATCH clause.

3.2.5.9. Equality and comparison of values

Equality

Cypher supports comparing values (see Section 3.2.1, “Values”) by equality using the = and <> operators.

Values of the same type are only equal if they are the same identical value (e.g. 3 = 3 and "x" <> "xy").

Maps are only equal if they map exactly the same keys to equal values and lists are only equal if they contain the same sequence of equal values (e.g. [3, 4] = [1+2, 8/2]).

Values of different types are considered as equal according to the following rules:

  • Paths are treated as lists of alternating nodes and relationships and are equal to all lists that contain that very same sequence of nodes and relationships.
  • Testing any value against null with both the = and the <> operators always is null. This includes null = null and null <> null. The only way to reliably test if a value v is null is by using the special v IS NULL, or v IS NOT NULL equality operators.

All other combinations of types of values cannot be compared with each other. Especially, nodes, relationships, and literal maps are incomparable with each other.

It is an error to compare values that cannot be compared.

3.2.5.10. Ordering and comparison of values

The comparison operators <=, < (for ascending) and >=, > (for descending) are used to compare values for ordering. The following points give some details on how the comparison is performed.

  • Numerical values are compared for ordering using numerical order (e.g. 3 < 4 is true).
  • The special value java.lang.Double.NaN is regarded as being larger than all other numbers.
  • String values are compared for ordering using lexicographic order (e.g. "x" < "xy").
  • Boolean values are compared for ordering such that false < true.
  • Comparing for ordering when one argument is null (e.g. null < 3 is null).
  • It is an error to compare other types of values with each other for ordering.

3.2.5.11. Chaining comparison operations

Comparisons can be chained arbitrarily, e.g., x < y <= z is equivalent to x < y AND y <= z.

Formally, if a, b, c, ..., y, z are expressions and op1, op2, ..., opN are comparison operators, then a op1 b op2 c ... y opN z is equivalent to a op1 b and b op2 c and ... y opN z.

Note that a op1 b op2 c does not imply any kind of comparison between a and c, so that, e.g., x < y > z is perfectly legal (although perhaps not elegant).

The example:

MATCH (n) WHERE 21 < n.age <= 30 RETURN n

is equivalent to

MATCH (n) WHERE 21 < n.age AND n.age <= 30 RETURN n

Thus it will match all nodes where the age is between 21 and 30.

This syntax extends to all equality and inequality comparisons, as well as extending to chains longer than three.

For example:

a < b = c <= d <> e

Is equivalent to:

a < b AND b = c AND c <= d AND d <> e

For other comparison operators, see Section 3.2.5.4, “Comparison operators”.