Cypher查询以按属性查找与其他节点不相关的节点 [英] Cypher query to find nodes that are not related to other node by property

问题描述

请考虑以下数据库结构:

Consider the following DB structure:

为方便起见，您可以使用以下方法创建它:

For your convenience, you can create it using:

create (p1:Person {name: "p1"}),(p2:Person {name: "p2"}),(p3:Person {name: "p3"}),(e1:Expertise {title: "Exp1"}),(e2:Expertise {title: "Exp2"}),(e3:Expertise {title: "Exp3"}),(p1)-[r1:Expert]->(e1),(p1)-[r2:Expert]->(e2),(p2)-[r3:Expert]->(e2),(p3)-[r4:Expert]->(e3),(p2)-[r5:Expert]->(e3)

我希望能够找到与特定Expertise节点不相关的所有Person节点，例如"Exp2"

I want to be able to find all Person nodes that are not related to a specific Expertise node, e.g. "Exp2"

我尝试过

MATCH (p:Person)--(e:Expertise)
WHERE NOT (e.title = "Exp2")
RETURN p

但是它返回所有Person节点(而我希望它仅返回p3).

But it returns all the Person nodes (while I expected it to return only p3).

从逻辑上讲，此结果是有意义的，因为这些节点中的每一个都与至少一个不是Exp2的Expertise相关.
但是我想要的是找到所有与Exp2不相关的Person节点，即使它们也与其他节点也相关.

Logically, this result makes sense because each of these nodes is related to at least one Expertise that is not Exp2.
But what I want is to find all the Person nodes that are not related to Exp2, even if they are related to other nodes as well.

这怎么办?

修改

看来我不清楚要求.这是(非常)简化的方法，可以用更复杂的数据库来表示我的问题.
考虑Expertise具有更多属性的可能性，这些属性我想在同一查询中使用(不一定带有否定).例如:

It appears that I wasn't clear on the requirements. This is a (very) simplified way of presenting my problem with a much more complicated DB.
Consider the possibility that Expertise has more properties which I would like to use in the same query (not necessarily with negation). For example:

MATCH (p)--(e) 
WHERE e.someProp > 5 AND e.anotherProp = "cookie" AND NOT e.title = "Exp2"

推荐答案

来自@ChristopheWillemsen的少量更改查询:

Little change query from @ChristopheWillemsen:

MATCH (e:Expertise) WHERE e.someProperty > 5 AND NOT e.title = someValue
WITH collect(e) as es
MATCH (p:Person) WHERE all(e in es WHERE NOT Exists( (p)--(e) ) )
RETURN p

更新:

// Collect the `Expertise` for which the following conditions:
MATCH (e:Expertise) WHERE e.num > 3 AND e.title = 'Exp2'
WITH collect(e) as es

// Select the users who do not connect with any of of expertise from `es` set:
OPTIONAL MATCH (p:Person) WHERE all(e in es WHERE NOT Exists( (p)--(e) ) )
RETURN es, collect(p)

另一个经过优化的查询:

Another query with some optimization:

// Get the set of `Expertise-node` for which the following conditions:
MATCH (e:Expertise) WHERE e.num > 3 AND e.title = 'Exp2'

// Collect all `Person-node` connected to node from the `Expertise-node` set:
OPTIONAL MATCH (e)--(p:Person)
WITH collect(e) as es, collect(distinct id(p)) as eps

//Get all `Person-node` not in `eps` set:
OPTIONAL MATCH (p:Person) WHERE NOT id(p) IN eps
RETURN es, collect(p)

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