Neo4j 统计相关节点个数

Question

I'm starting studying the Neo4j and the Cypher Queries, and I need some help to understand and get some results.

I have this MATCH query:

MATCH (p:EntidadePessoa {id: 168750})-[rd:SE_RELACIONA]->(d:Documento)<--(p2) 
 where p2:EntidadePessoa or p2:EntidadeOrganizacao 
 return p,d,p2

That results this:

Commencing with EntidadePessoa id:168750, I want the count of EntidadeDocumento directcly linked to EntidadePessoa id:168750, is this case 2, and the count of each Entidade* that is linked to EntidadeDocumento, in this case 4 for each EntidadeDocumento.

I tried some queries, but none give me the results I wanted, the count number is never the numbers I wanted.

Could you help with that?

Answer 1

1. A query to get the count of d nodes connected to p (id: 168750).

    MATCH (p:EntidadePessoa {id: 168750})-[rd:SE_RELACIONA]->(d:Documento)
    RETURN p.id as `nodeId`, count(d) as `connectedCount`

output:

 nodeId connectedCount 168750 2

2. A query with a subquery to look at just d:Documento, incoming links from p2, omitting (p:EntidadePessoa {id: 168750}) and counting p2s for each d node:

    CALL
    {MATCH (p)-[rd:SE_RELACIONA]->(d:Documento)
    WHERE p.id=168750
    RETURN  d,p.id as `topid`}
    MATCH (p2)-->(d)
    WHERE (p2:EntidadePessoa or p2:EntidadeOrganizacao) AND p2.id<>topid
    //p2.id<>topid ensures p is not included in count(p2) 
    RETURN d.id as `nodeId`, count(p2) as `connectedCount`

output:

 nodeId connectedCount 164532 4 164552 4

3. Combine both these results with a UNION:

    MATCH (p:EntidadePessoa {id: 168750})-[rd:SE_RELACIONA]->(d:Documento)
    RETURN p.id as `nodeId`, count(d) as `connectedCount`UNION
    CALL
    {MATCH (p)-[rd:SE_RELACIONA]->(d:Documento)
    WHERE p.id=168750
    RETURN  d,p.id as `topid`}
    MATCH (p2)-->(d)
    WHERE (p2:EntidadePessoa or p2:EntidadeOrganizacao) AND p2.id<>topid
    //p2.id<>topid ensures p is not included in count(p2) 
    RETURN d.id as `nodeId`, count(p2) as `connectedCount`

output:

 nodeId connectedCount 168750 2 164552 4 164552 4

Answer 2

This will give you the result. This is similar to count and group_by in sql.

 MATCH (p:EntidadePessoa {id: 168750})-[rd:SE_RELACIONA]->(d:Documento)<--(p2) 
  where p2:EntidadePessoa or p2:EntidadeOrganizacao 
 With p, count(distinct d) as cnt_d, count(p2) as cnt_p2
  return p, cnt_d, cnt_p2