Remove paths which are subsets of a longer path - graph

Question

I would like to obtain the longest path that are connected to a single parent via Neo4J Cypher query.
My current queries are like this:
MATCH p=(N1:Node)-[REL*..2]->(N2:Node) WHERE N2.RIC =~"some ticker.*" RETURN p limit 50
However, i am getting results like this
a->b->parent
b-> parent
In my own opinion , i would like to keep only the longest path.
Also, is there anyway to return the direction of the query ? IE: i can see the from/to of a relationship in the output of the query.
Thanking in advance !

Answer 1

If you want just the longest path then you can do:
MATCH path=(N1:Node)-[REL*..2]->(N2:Node)
WHERE N2.RIC =~"some ticker.*"
RETURN p
ORDER BY length(p) DESC
LIMIT 1
As for getting the directions, this depends on the driver that you use. In the Neo4j HTTP transaction endpoint if you specify REST for resultDataContents, it will return a directions for any path objects that you return. Here is how you set that:
http://neo4j.com/docs/stable/rest-api-transactional.html#rest-api-execute-statements-in-an-open-transaction-in-rest-format-for-the-return
Here is an example of what that looks like:
"rest": [
{
"relationships": [
"http://localhost:7474/db/data/relationship/587"
],
"nodes": [
"http://localhost:7474/db/data/node/1002",
"http://localhost:7474/db/data/node/1001"
],
"directions": [
"<-"
],
"length": 1,
"start": "http://localhost:7474/db/data/node/1002",
"end": "http://localhost:7474/db/data/node/1001"
}
]
EDIT:
Responding to your comment, in order to get the longest path for each parent:
MATCH path=(N1:Node)-[REL*..2]->(N2:Node)
WHERE N2.RIC =~"some ticker.*"
WITH N1, N2, collect(p) AS paths
ORDER BY length(p) DESC
RETURN N1, N2, paths[0] AS longest_path
I wasn't sure which side is supposed to be the parent, so I returned both N1 and N2 which should give you the longest path for each combination of those two. You can remove either one to get the longest path leading to/from the node which is left.