Question

如果你想查询特定节点类型和相关节点解决方案很简单，通过使用collect函数我们可以实现这个目标，如return country，collect（city）as c

但是，如果我们需要检索像血统或用户的数据树，那么我们应该怎么做 - ＆gt; post-＆gt; comment-＆gt; like 有什么解决方案可以在cypher输出中处理这种数据吗？

Answer 1

给出以下图表：

CREATE (user:User { id: 0 })
CREATE (post:Post)
CREATE (comment:Comment)
CREATE (user)-[:POSTED]->(post)<-[:ON]-(comment)<-[:COMMENTED]-(user)
CREATE (user)-[:LIKES]->(comment)

使用以下查询检索可变长度路径：

MATCH (user:User { id: 0 })
MATCH p=(user)-[*]->(post)
RETURN p
ORDER BY length(p) DESC

这导致以下输出：

+----------------------------------------------------------------+
| p                                                              |
+----------------------------------------------------------------+
| [Node[6]{id:0},:COMMENTED[8] {},Node[8]{},:ON[7] {},Node[7]{}] |
| [Node[6]{id:0},:LIKES[9] {},Node[8]{},:ON[7] {},Node[7]{}]     |
| [Node[6]{id:0},:POSTED[6] {},Node[7]{}]                        |
| [Node[6]{id:0},:COMMENTED[8] {},Node[8]{}]                     |
| [Node[6]{id:0},:LIKES[9] {},Node[8]{}]                         |
+----------------------------------------------------------------+
5 rows
19 ms

要查看相关内容和方式，请运行以下查询：

// What is related, and how
MATCH (a)-[r]->(b)
WHERE labels(a) <> [] AND labels(b) <> []
RETURN DISTINCT head(labels(a)) AS This, type(r) as To, head(labels(b)) AS That
LIMIT 10

结果如下：

+-------------------------------------+
| This      | To          | That      |
+-------------------------------------+
| "User"    | "POSTED"    | "Post"    |
| "User"    | "COMMENTED" | "Comment" |
| "User"    | "LIKES"     | "Comment" |
| "Comment" | "ON"        | "Post"    |
+-------------------------------------+
4 rows
139 ms

Neo4j cypher查询检索数据树

1 个答案: