Question

我有两种节点类型可以说类型＆＃39;学生＆＃39;和老师＆＃39;

Student have {id, name}.
Teacher have {id, name}.

学生可以与班级节点建立选择关系＆＃39; TEACHES＆＃39;。

(t:Teacher)-[r:TEACHES]->(c:Student).

[r:TEACHES] - Optional relationship. (present or may not present)

我想找到＆＃34;学生＆＃34;没有老师的节点。即没有任何传入关系＆＃34; TEACHES＆＃34;

请帮忙。

Answer 1

我认为你正在寻找这种模式。

MATCH (s:Student)
WHERE NOT (s)<-[:TEACHES]-(:Teacher)
RETURN s

Answer 2

这是一个简单的数据设置，以及您需要解决问题的底部查询。从本质上讲，您希望查询关系不存在的情况。这里的语法适用于neo4j 2.0，因此旧版本的答案会略有不同。

neo4j-sh (?)$ create (t:Teacher {name:"Bob"})-[r:TEACHES]->(s:Student {name:"Mary"});
+-------------------+
| No data returned. |
+-------------------+
Nodes created: 2
Relationships created: 1
Properties set: 2
Labels added: 2
19 ms

neo4j-sh (?)$ create (t:Teacher {name:"Mark"});
+-------------------+
| No data returned. |
+-------------------+
Nodes created: 1
Properties set: 1
Labels added: 1
5 ms

neo4j-sh (?)$ MATCH (s:Student) WHERE NOT (s)<-[:TEACHES]-(:Teacher) RETURN s

Answer 3

我得到了结果。首先匹配学生标准，然后找到关系为空

MATCH (s:Student)
OPTIONAL MATCH (t:Teacher)-[r:TEACHES]->(s)
WITH s,r
WHERE r IS NULL
RETURN s.name

如何在neo4j中找到没有传入关系的节点

3 个答案: