ORDER BY

Overview

The ORDER BY statement allows you to sort the intermediate result or output table based on the specified columns.

<order by statement> ::= 
  "ORDER BY" <sort specification> [ { "," <sort specification> }... ]

<sort specification> ::=
  <value expression> [ "ASC" | "DESC" ] [ "NULLS FIRST" | "NULLS LAST" ]

Details

• ASC (ascending) is applied by default. To reverse the order, you can explicitly use the DESC (descending) keyword.
• NULLS FIRST and NULLS LAST can be used to control whether null values appear before or after non-null values. When null ordering is not explicitly specified:
  • NULLS LAST is applied by default when ordering in the ASC order.
  • NULLS FIRST is applied by default when ordering in the DESC order.

Example Graph

CREATE GRAPH myGraph { 
  NODE Paper ({title string, score uint32, author string, publisher string}),
  EDGE Cites ()-[{weight uint32}]->()
} PARTITION BY HASH(Crc32) SHARDS [1]

INSERT (p1:Paper {_id:'P1', title:'Efficient Graph Search', score:6, author:'Alex', publisher:'PulsePress'}),
       (p2:Paper {_id:'P2', title:'Optimizing Queries', score:9, author:'Alex'}),
       (p3:Paper {_id:'P3', title:'Path Patterns', score:7, author:'Zack', publisher:'BrightLeaf'}),
       (p1)-[:Cites {weight:2}]->(p2),
       (p2)-[:Cites {weight:1}]->(p3)

Ordering by Property

MATCH (n:Paper)
ORDER BY n.score
RETURN n.title, n.score

Result:

Ordering by Node or Edge Variable

When a node or edge variable is specified, it is sorted on the _uuid of the nodes or edges.

MATCH (n:Paper)
RETURN n.title, element_id(n) ORDER BY n

Result:

Ordering by Expression

MATCH p = (:Paper)->{1,2}(:Paper)
RETURN p, path_length(p) AS length ORDER BY length DESC

Result:

p	length
	2
	1
	1

Multi-level Ordering

When there are multiple specifications, it is sorted by the first specification listed, and for equals values, go to the next specification, and so on.

MATCH (n:Paper)
RETURN n.title, n.author, n.score 
ORDER BY n.author DESC, n.score

Result:

Discarding and Retaining Records After Ordering

You may use the SKIP or LIMIT statement after the ORDER BY statement to skip a specified number of records from the top, or to limit the number of records retained.

To return titles of the two papers with the second and third highest scores:

MATCH (n:Paper)
RETURN n.title, n.score
ORDER BY n.score DESC SKIP 1 LIMIT 2

Result:

Null Ordering

To return titles of the two papers with the second and third highest scores, ensuring null values appear at the front if applicable:

MATCH (n:Paper)
RETURN n.title, n.publisher
ORDER BY n.publisher NULLS FIRST

Result: