2018-11-21

3.9. Glossary of keywords

This section comprises a glossary of all the keywords — grouped by category and thence ordered lexicographically — in the Cypher query language.

3.9.1. Clauses

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Clause

Category

Description

CALL […​YIELD]

|

Reading/Writing

|

Invoke a procedure deployed in the database.

| |

CREATE

|

Writing

|

Create nodes and relationships.

| |

CREATE CONSTRAINT ON (n:Label) ASSERT exists(n.property)

|

Schema

|

Create a constraint ensuring that all nodes with a particular label have a certain property.

| |

CREATE CONSTRAINT ON (n:Label) ASSERT (n.prop1, …​, n.propN) IS NODE KEY

|

Schema

|

Create a constraint ensuring all nodes with a particular label have all the specified properties and that the combination of property values is unique; i.e. ensures existence and uniqueness.

| |

CREATE CONSTRAINT ON ()-[r:REL_TYPE]-() ASSERT exists(r.property)

|

Schema

|

Create a constraint ensuring that all relationship with a particular type have a certain property.

| |

CREATE CONSTRAINT ON (n:Label) ASSERT n.property IS UNIQUE

|

Schema

|

Create a constraint ensuring the uniqueness of the combination of node label and property value for a particular property key across all nodes.

| |

CREATE INDEX ON :Label(property)

|

Schema

|

Create an index on all nodes with a particular label and a single property; i.e. create a single-property index.

| |

CREATE INDEX ON :Label(prop1, …​, propN)

|

Schema

|

Create an index on all nodes with a particular label and multiple properties; i.e. create a composite index.

| |

DELETE

|

Writing

|

Delete graph elements — nodes, relationships or paths. Any node to be deleted must also have all associated relationships explicitly deleted.

| |

DETACH DELETE

|

Writing

|

Delete a node or set of nodes. All associated relationships will automatically be deleted.

| |

DROP CONSTRAINT ON (n:Label) ASSERT exists(n.property)

|

Schema

|

Drop a constraint ensuring that all nodes with a particular label have a certain property.

| |

DROP CONSTRAINT ON ()-[r:REL_TYPE]-() ASSERT exists(r.property)

|

Schema

|

Drop a constraint ensuring that all relationship with a particular type have a certain property.

| |

DROP CONSTRAINT ON (n:Label) ASSERT n.property IS UNIQUE

|

Schema

|

Drop a constraint ensuring the uniqueness of the combination of node label and property value for a particular property key across all nodes.

| |

DROP CONSTRAINT ON (n:Label) ASSERT (n.prop1, …​, n.propN) IS NODE KEY

|

Schema

|

Drop a constraint ensuring all nodes with a particular label have all the specified properties and that the combination of property values is unique.

| |

DROP INDEX ON :Label(property)

|

Schema

|

Drop an index from all nodes with a particular label and a single property; i.e. drop a single-property index.

| |

DROP INDEX ON :Label(prop1, …​, propN)

|

Schema

|

Drop an index from all nodes with a particular label and multiple properties; i.e. drop a composite index.

| |

FOREACH

|

Writing

|

Update data within a list, whether components of a path, or the result of aggregation.

| |

LIMIT

|

Reading sub-clause

|

A sub-clause used to constrain the number of rows in the output.

| |

LOAD CSV

|

Importing data

|

Use when importing data from CSV files.

| |

MATCH

|

Reading

|

Specify the patterns to search for in the database.

| |

MERGE

|

Reading/Writing

|

Ensures that a pattern exists in the graph. Either the pattern already exists, or it needs to be created.

| |

ON CREATE

|

Reading/Writing

|

Used in conjunction with MERGE, specifying the actions to take if the pattern needs to be created.

| |

ON MATCH

|

Reading/Writing

|

Used in conjunction with MERGE, specifying the actions to take if the pattern already exists.

| |

OPTIONAL MATCH

|

Reading

|

Specify the patterns to search for in the database while using nulls for missing parts of the pattern.

| |

ORDER BY [ASC[ENDING] | DESC[ENDING]]

|

Reading sub-clause

|

A sub-clause following RETURN or WITH, specifying that the output should be sorted in either ascending (the default) or descending order.

| |

REMOVE

|

Writing

|

Remove properties and labels from nodes and relationships.

| |

RETURN …​ [AS]

|

Projecting

|

Defines what to include in the query result set.

| |

SET

|

Writing

|

Update labels on nodes and properties on nodes and relationships.

| |

SKIP

|

Reading/Writing

|

A sub-clause defining from which row to start including the rows in the output.

| |

UNION

|

Set operations

|

Combines the result of multiple queries. Duplicates are removed.

| |

UNION ALL

|

Set operations

|

Combines the result of multiple queries. Duplicates are retained.

| |

UNWIND …​ [AS]

|

Projecting

|

Expands a list into a sequence of rows.

| |

USING INDEX variable:Label(property)

|

Hint

|

Index hints are used to specify which index, if any, the planner should use as a starting point.

| |

USING INDEX SEEK variable:Label(property)

|

Hint

|

Index seek hint instructs the planner to use an index seek for this clause.

| |

USING JOIN ON variable

|

Hint

|

Join hints are used to enforce a join operation at specified points.

| |

USING PERIODIC COMMIT

|

Hint

|

This query hint may be used to prevent an out-of-memory error from occurring when importing large amounts of data using LOAD CSV.

| |

USING SCAN variable:Label

|

Hint

|

Scan hints are used to force the planner to do a label scan (followed by a filtering operation) instead of using an index.

| |

WITH …​ [AS]

|

Projecting

|

Allows query parts to be chained together, piping the results from one to be used as starting points or criteria in the next.

| |

WHERE

|

Reading sub-clause

|

A sub-clause used to add constraints to the patterns in a MATCH or OPTIONAL MATCHclause, or to filter the results of a WITH clause.

|

3.9.2. Operators

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Operator

Category

Description

%

|

Mathematical

|

Modulo division

| |

*

|

Mathematical

|

Multiplication

| |

+

|

Mathematical

|

Addition

| |

+

|

String

|

Concatenation

| |

+

|

List

|

Concatenation

| |

-

|

Mathematical

|

Subtraction or unary minus

| |

.

|

General

|

Property access

| |

/

|

Mathematical

|

Division

| |

<

|

Comparison

|

Less than

| |

<=

|

Comparison

|

Less than or equal to

| |

<>

|

Comparison

|

Inequality

| |

=

|

Comparison

|

Equality

| |

=~

|

String

|

Regular expression match

| |

>

|

Comparison

|

Greater than

| |

>=

|

Comparison

|

Greater than or equal to

| |

AND

|

Boolean

|

Conjunction

| |

CONTAINS

|

String comparison

|

Case-sensitive inclusion search

| |

DISTINCT

|

General

|

Duplicate removal

| |

ENDS WITH

|

String comparison

|

Case-sensitive suffix search

| |

IN

|

List

|

List element existence check

| |

IS NOT NULL

|

Comparison

|

Non-null check

| |

IS NULL

|

Comparison

|

null check

| |

NOT

|

Boolean

|

Negation

| |

OR

|

Boolean

|

Disjunction

| |

STARTS WITH

|

String comparison

|

Case-sensitive prefix search

| |

XOR

|

Boolean

|

Exclusive disjunction

| |

[]

|

General

|

Subscript (dynamic property access)

| |

[]

|

List

|

Subscript (accessing element(s) in a list)

| |

^

|

Mathematical

|

Exponentiation

|

3.9.3. Functions

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Function

Category

Description

abs()

|

Numeric

|

Returns the absolute value of a number.

| |

acos()

|

Trigonometric

|

Returns the arccosine of a number in radians.

| |

all()

|

Predicate

|

Tests whether the predicate holds for all elements in a list.

| |

any()

|

Predicate

|

Tests whether the predicate holds for at least one element in a list.

| |

asin()

|

Trigonometric

|

Returns the arcsine of a number in radians.

| |

atan()

|

Trigonometric

|

Returns the arctangent of a number in radians.

| |

atan2()

|

Trigonometric

|

Returns the arctangent2 of a set of coordinates in radians.

| |

avg()

|

Aggregating

|

Returns the average of a set of values.

| |

ceil()

|

Numeric

|

Returns the smallest floating point number that is greater than or equal to a number and equal to a mathematical integer.

| |

coalesce()

|

Scalar

|

Returns the first non-null value in a list of expressions.

| |

collect()

|

Aggregating

|

Returns a list containing the values returned by an expression.

| |

cos()

|

Trigonometric

|

Returns the cosine of a number.

| |

cot()

|

Trigonometric

|

Returns the cotangent of a number.

| |

count()

|

Aggregating

|

Returns the number of values or rows.

| |

degrees()

|

Trigonometric

|

Converts radians to degrees.

| |

distance()

|

Spatial

|

Returns a floating point number representing the geodesic distance between any two points in the same CRS.

| |

e()

|

Logarithmic

|

Returns the base of the natural logarithm, e.

| |

endNode()

|

Scalar

|

Returns the end node of a relationship.

| |

exists()

|

Predicate

|

Returns true if a match for the pattern exists in the graph, or if the specified property exists in the node, relationship or map.

| |

exp()

|

Logarithmic

|

Returns e^n, where e is the base of the natural logarithm, and n is the value of the argument expression.

| |

extract()

|

List

|

Returns a list l<sub>result</sub> containing the values resulting from an expression which has been applied to each element in a list list.

| |

filter()

|

List

|

Returns a list l<sub>result</sub> containing all the elements from a list list that comply with a predicate.

| |

floor()

|

Numeric

|

Returns the largest floating point number that is less than or equal to a number and equal to a mathematical integer.

| |

haversin()

|

Trigonometric

|

Returns half the versine of a number.

| |

head()

|

Scalar

|

Returns the first element in a list.

| |

id()

|

Scalar

|

Returns the id of a relationship or node.

| |

keys()

|

List

|

Returns a list containing the string representations for all the property names of a node, relationship, or map.

| |

labels()

|

List

|

Returns a list containing the string representations for all the labels of a node.

| |

last()

|

Scalar

|

Returns the last element in a list.

| |

left()

|

String

|

Returns a string containing the specified number of leftmost characters of the original string.

| |

length()

|

Scalar

|

Returns the length of a path.

| |

log()

|

Logarithmic

|

Returns the natural logarithm of a number.

| |

log10()

|

Logarithmic

|

Returns the common logarithm (base 10) of a number.

| |

lTrim()

|

String

|

Returns the original string with leading whitespace removed.

| |

max()

|

Aggregating

|

Returns the maximum value in a set of values.

| |

min()

|

Aggregating

|

Returns the minimum value in a set of values.

| |

nodes()

|

List

|

Returns a list containing all the nodes in a path.

| |

none()

|

Predicate

|

Returns true if the predicate holds for no element in a list.

| |

percentileCont()

|

Aggregating

|

Returns the percentile of the given value over a group using linear interpolation.

| |

percentileDisc()

|

Aggregating

|

Returns the nearest value to the given percentile over a group using a rounding method.

| |

pi()

|

Trigonometric

|

Returns the mathematical constant pi.

| |

point() - cartesian 2D

|

Spatial

|

Returns a point object, given two coordinate values in the cartesian coordinate system.

| |

point() - WGS 84

|

Spatial

|

Returns a point object, given two coordinate values in the WGS 84 coordinate system.

| |

properties()

|

Scalar

|

Returns a map containing all the properties of a node or relationship.

| |

radians()

|

Trigonometric

|

Converts degrees to radians.

| |

rand()

|

Numeric

|

Returns a random floating point number in the range from 0 (inclusive) to 1 (exclusive); i.e. [0, 1).

| |

range()

|

List

|

Returns a list comprising all integer values within a specified range.

| |

reduce()

|

List

|

Runs an expression against individual elements of a list, storing the result of the expression in an accumulator.

| |

relationships()

|

List

|

Returns a list containing all the relationships in a path.

| |

replace()

|

String

|

Returns a string in which all occurrences of a specified string in the original string have been replaced by another (specified) string.

| |

reverse()

|

List

|

Returns a list in which the order of all elements in the original list have been reversed.

| |

reverse()

|

String

|

Returns a string in which the order of all characters in the original string have been reversed.

| |

right()

|

String

|

Returns a string containing the specified number of rightmost characters of the original string.

| |

round()

|

Numeric

|

Returns the value of a number rounded to the nearest integer.

| |

rTrim()

|

String

|

Returns the original string with trailing whitespace removed.

| |

sign()

|

Numeric

|

Returns the signum of a number: 0 if the number is 0, -1 for any negative number, and 1 for any positive number.

| |

sin()

|

Trigonometric

|

Returns the sine of a number.

| |

single()

|

Predicate

|

Returns true if the predicate holds for exactly one of the elements in a list.

| |

size()

|

Scalar

|

Returns the number of items in a list.

| |

size() applied to pattern expression

|

Scalar

|

Returns the number of sub-graphs matching the pattern expression.

| |

size() applied to string

|

Scalar

|

Returns the size of a string.

| |

split()

|

String

|

Returns a list of strings resulting from the splitting of the original string around matches of the given delimiter.

| |

sqrt()

|

Logarithmic

|

Returns the square root of a number.

| |

startNode()

|

Scalar

|

Returns the start node of a relationship.

| |

stDev()

|

Aggregating

|

Returns the standard deviation for the given value over a group for a sample of a population.

| |

stDevP()

|

Aggregating

|

Returns the standard deviation for the given value over a group for an entire population.

| |

substring()

|

String

|

Returns a substring of the original string, beginning with a 0-based index start and length.

| |

sum()

|

Aggregating

|

Returns the sum of a set of numeric values.

| |

tail()

|

List

|

Returns all but the first element in a list.

| |

tan()

|

Trigonometric

|

Returns the tangent of a number.

| |

timestamp()

|

Scalar

|

Returns the difference, measured in milliseconds, between the current time and midnight, January 1, 1970 UTC.

| |

toBoolean()

|

Scalar

|

Converts a string value to a boolean value.

| |

toFloat()

|

Scalar

|

Converts an integer or string value to a floating point number.

| |

toInteger()

|

Scalar

|

Converts a floating point or string value to an integer value.

| |

toLower()

|

String

|

Returns the original string in lowercase.

| |

toString()

|

String

|

Converts an integer, float or boolean value to a string.

| |

toUpper()

|

String

|

Returns the original string in uppercase.

| |

trim()

|

String

|

Returns the original string with leading and trailing whitespace removed.

| |

type()

|

Scalar

|

Returns the string representation of the relationship type.

|

3.9.4. Expressions

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Name

Description

CASE Expression

|

A generic conditional expression, similar to if/else statements available in other languages.

|

3.9.5. Cypher query options

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Name

Type

Description

CYPHER $version query

|

Version

|

This will force 'query' to use Neo4j Cypher $version. The default is 3.2.

| |

CYPHER planner=rule query

|

Planner

|

This will force 'query' to use the rule planner. As the rule planner has been removed in 3.2, doing this will cause 'query' to fall back to using Cypher 3.1.

| |

CYPHER planner=cost query

|

Planner

|

Neo4j 3.2 uses the cost planner for all queries.

| |

CYPHER runtime=interpreted query

|

Runtime

|

This will cause the query execution engine to disregard the compiled runtime, and therefore use the interpreted runtime. This is the only option in Neo4j Community Edition.

| |

CYPHER runtime=compiled query

|

Runtime

|

This will cause the query execution engine to use the compiled runtime if it supports 'query', and fall back to using the interpreted runtime if it does not. This is only available in Neo4j Enterprise Edition.

|

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