Cypher -Tally报告源自父节点的每种关系类型的深度 [英] Cypher -Tally report on the depth of each relationship type stemming from parent node

问题描述

我试图针对源自父节点的每种关系类型的深度创建统计报告，但遇到以下错误:

I am trying to create tally report on the depth of each relationship type stemming from parent node but I running into issues with the following error:

"Type mismatch: r already defined with conflicting type Relationship (expected Collection<Relationship>)

这是我试图实现的输出:

Here is the output I am attempting to achieve:

[
   {
      reltype    : "123A_RelationshipTitleOne",
      depthcount : 5
   }, {
      reltype    : "123A_RelationshipTitleTwo",
      depthcount : 9
   }, {
      reltype    : "123A_RelationshipTitleThree",
      depthcount : 42
   }
]

这是我的密码查询尝试，它产生上述错误.我使用一个变量代替了"123A"，但在这里我将"123A"用作清晰的工作示例:

Here is my cypher query attempt that generates the error mentioned above. In place of '123A' I use a a variable but I used '123A' as a legible working example here:

MATCH (n {id: '123A'})
OPTIONAL MATCH (n)-[r]-()
WHERE left( type(r), LENGTH( '123A' )) = '123A'
OPTIONAL MATCH p=(n)-[r*]->(c)
WITH n, COLLECT({
    id    : type(r),
    count : MAX(length(p))
}) AS leafreport
RETURN n, leafreport

非常感谢您能提供的帮助.

I am very grateful for help you can offer.

推荐答案

使用绑定变量r首先表示一个关系，然后(在第二个OPTIONAL MATCH中)一个Collection引起type mismatch错误关系.

The type mismatch error is being caused by using the bound variable r to represent first a relationship and then (in the second OPTIONAL MATCH) a Collection of relationships.

在模式(n)-[r*]->(c)中，r*表示可变长度路径，因此r绑定到与可变长度模式匹配的关系的集合.但是，r之前已绑定到OPTIONAL MATCH (n)-[r]-()中的关系，因此会出现错误.如果要检查路径p中是否包含r，请使用WHERE子句.像这样:

In the pattern (n)-[r*]->(c), r* indicates a variable length path so r is bound to a Collection of relationships that match the variable length pattern. However r was previously bound to a relationship in OPTIONAL MATCH (n)-[r]-(), thus the error. If you want to check that r is in the path, p, use a WHERE clause. Something like this:

MATCH (n {id: '123A'})
MATCH (n)-[r]-()
WHERE left( type(r), LENGTH( '123A' )) = '123A'
MATCH p=(n)-[rs*]->(c) WHERE r IN rs
WITH n, {
    id    : type(r),
    count : MAX(length(p))
} AS leafreport
RETURN n, leafreport

我认为您不希望第二个OPTIONAL MATCH是可选的，因此我将其更改为MATCH子句

I don't think you want the second OPTIONAL MATCH to be optional, so I changed it to a MATCH clause

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