Value Query Expression

The value query expression allows you to specify a scalar value derived from a nested query specification. The output of this expression is expected to be either a single value or null.

Syntax
<value query expression> ::= "VALUE" "{" <query> "}"

Details

• The <query> must conclude with a result statement that adheres to the following requirements:
  • Must include a RETURN statement with a single return item, and must not contain GROUP BY.
  • The return item in the RETURN statement must either utilize an aggregation function or explicitly include LIMIT 1. If neither is specified, LIMIT 1 will be implicitly applied to ensure only a single result is returned.

Example Graph

GQL
INSERT (p1:Paper {_id:'P1', title:'Efficient Graph Search', score:6}),
       (p2:Paper {_id:'P2', title:'Optimizing Queries', score:9}),
       (p3:Paper {_id:'P3', title:'Path Patterns', score:7}),
       (p1)-[:Cites]->(p2),
       (p2)-[:Cites]->(p3)

Examples

GQL
LET avgScore = VALUE {MATCH (n) RETURN avg(n.score)}
MATCH (n) WHERE n.score > avgScore
RETURN n.title

Result: