CODEWITHSUNDEEP
neo4jcyphergraph-databases
Oliver
Oliver

Reputation: 4193

How to return a list of related nodes for each node in Cypher

I would like to write a query for the graph below, which should return three lists, each list containing all persons working for the same person.

Given the graph below, the result should be this three lists:

Graph of work relationships

I fail to write such query. My query returns all employes in one list.

The following statements create the graph model for the example I have given:

MATCH  (c:Example) DETACH DELETE c;

CREATE (p1:Parent:Example {id: 1, name: 'Andy', title: 'Developer'});
CREATE (p2:Parent:Example {id: 2, name: 'Lila', title: 'Developer'});
CREATE (p3:Parent:Example {id: 3, name: 'Lula', title: 'Developer'});

CREATE (c11:Child:Example {id: 11, name: 'Peter', title: 'Developer'});
CREATE (c12:Child:Example {id: 12, name: 'Susy', title: 'Developer'});

CREATE (c21:Child:Example {id: 21, name: 'Fritz', title: 'Developer'});

CREATE (c31:Child:Example {id: 31, name: 'Pepe', title: 'Developer'});

MATCH (p {id: 1}), (c {id: 11}) MERGE (p)<-[:WORKS_FOR]-(c);
MATCH (p {id: 1}), (c {id: 12}) MERGE (p)<-[:WORKS_FOR]-(c);
MATCH (p {id: 2}), (c {id: 21}) MERGE (p)<-[:WORKS_FOR]-(c);
MATCH (p {id: 3}), (c {id: 31}) MERGE (p)<-[:WORKS_FOR]-(c);

Upvotes: 1

Views: 47

Answers (1)

Christophe Willemsen
Christophe Willemsen

Reputation: 20185

It's relatively straightforward with Cypher

MATCH (c)-[:WORKS_FOR]->(p)
RETURN p.name AS boss, collect(c.name) AS coWorkers

Result

╒══════╤════════════════╕
│"boss"│"coWorkers"     │
╞══════╪════════════════╡
│"Andy"│["Peter","Susy"]│
├──────┼────────────────┤
│"Lila"│["Fritz"]       │
├──────┼────────────────┤
│"Lula"│["Pepe"]        │
└──────┴────────────────┘

The trick is understanding aggregations https://neo4j.com/docs/cypher-manual/current/functions/aggregating/#grouping-keys

Upvotes: 2

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