如何找到Neo4j和Cypher中的一系列连接节点的头部？

Question

I'm still quite new with Neo4j and I thought this would be a really easy task but after some serious goolging I realized it's probably not so easy (or I just used the wrong keywords...)

I'm trying to find the head of a series of nodes connected with a particular relationship. The relationship is based on the timestamp property of each node. Here's my first attempt query:

MATCH (n1)-[:RELATIONSHIP*]->()
ORDER BY n1.timestamp
RETURN n1

Then I found the startNode function and tried:

MATCH ()-[rel:RELATIONSHIP]->()
RETURN startNode(rel)

But it doesn't always return the start nodes. Sometimes it returns some nodes in the middle. I'd like to find all of the heads and connect them to nodes of some other labels. Thanks!

Answer 1

Turned out the answer is extremely easy...thanks to @tomasi from the Neo4j Slack Group.

Here in case anyone needs it:

MATCH (n:Label)
WHERE NOT ()-[:RELATIONSHIP]->(n)
RETURN n