Neo4j查询-查找满足属性条件并具有关系的所有节点

Question

我有一个成功运行的查询：

match (n:A {tag_no:"N2203"})<-[:rel_a]-(v:B)-[:rel_b]->(r)<-[:rel_c]-(n) WHERE (v.invoice_date>="2012-08-01" AND v.invoice_date<"2016-02-01") with v, collect(r) as rs where all (x in rs where x.date<"2016-08-01") return count(v) as count;

我需要进一步过滤此查询。

我需要r nodes with max(r.date) for each v关联r nodes with max(r.date) for each v ，并找出其中有多少个节点与另一个D类型的节点有关系

我正在尝试此查询，它引发语法错误

match (n:A {tag_no:"N2203"})<-[:rel_a]-(v:B)-[:rel_b]->(r)<-[:rel_c]-(n) WHERE (v.invoice_date>="2012-08-01" AND v.invoice_date<"2016-02-01") with v, max(r.date) as date collect(r) as rs where (all (x in rs where x.date<"2016-08-01") AND filter(x in rs where x.date=date)[0]<-[:rel_c]-(d:D)) return count(v) as count;

我还尝试了许多其他组合，但是都抛出了一些语法错误。 感谢所有帮助。

Answer 1

主要问题是查询解析器现在无法确定filter(x in rs where x.date=date)[0]确实是一个节点，因此语法中不允许这样做。 幸运的是，有可能以一些冗长的代价解决此问题：

• 使用另一个WITH子句为节点变量引入别名（ n ）。 这将允许您使用WHERE <pattern>语法。
• 同样，您不能在WHERE子句中引入新变量，因此只需使用(:D)而不是(d:D) 。

因此查询将如下所示（显然，我尚未对其进行测试）：

MATCH (n:A {tag_no:"N2203"})<-[:rel_a]-(v:B)-[:rel_b]->(r)<-[:rel_c]-(n)
WHERE v.invoice_date>="2012-08-01"
  AND v.invoice_date<"2016-02-01"
WITH
  v,
  max(r.date) AS date,
  collect(r) AS rs
WHERE all(x IN rs WHERE x.date<"2016-08-01")
WITH filter(x in rs where x.date=date)[0] AS n, v
WHERE (n)<-[:rel_c]-(:D)
RETURN count(v) AS count;