Comparing relationship properties within a path
You want to compare relationship-properties of a path, either by a global value or parameter, or with each other within a path.
Basic model:
(:Person {person_id:'123'})-[:FRIEND {date:'1972-01-01'}]->(m:Person {person_id:'456'})
Make sure to have an constraint OR index on your nodes:
Constraint
CREATE CONSTRAINT ON (p:Person) ASSERT p.person_id IS UNIQUE
Index
CREATE INDEX ON :Person(person_id);
If you have your time in yyyy-mm-dd
you can compare them directly: (with 2 digits aka 01
) i.e. '2012-01-10' > '2011-08-31'
)
WITH '1962-01-01' AS maxdate
MATCH (n:Person)-[f1:FRIEND]-()-[f2:FRIEND]-(m:Person)
WHERE n.person_id='180' AND f1.date < maxdate AND f2.date < maxdate
RETURN m;
You can also use the short form: (n:Person {person_id:'180'})
:
If you want to have a general expression on relationships in a path, use a variable rels
(which is then a collection) within your variable-length-path pattern:
WITH '1962-01-01' AS maxdate
MATCH (n:Person {person_id:'180'})-[rels:FRIEND*2]-(m:Person)
WHERE ALL(r IN rels WHERE r.date < maxdate)
RETURN m;
You can also use rels(path)
function.
WITH '1962-01-01' AS maxdate
MATCH path = (n:Person {person_id:'180'})-[:FRIEND*2]-(m:Person)
WHERE ALL(r in rels(path) WHERE r.date < maxdate)
RETURN m;
Or if the relationships of a path are in relation to each other:
WITH '1962-01-01' AS maxdate
MATCH (n:Person {person_id:'180'})-[rels:FRIEND*2]-(m:Person)
WHERE ALL(idx in range(0, size(rels)-2) WHERE (rels[idx]).date < maxdate AND (rels[idx]).date < (rels[idx+1]).date)
RETURN m;
Original question was on StackOverflow
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