Why don't these Cypher queries do the same thing? - neo4j

Question

I am matching a full path, deleting the last node and then walking back up the nodes to delete any that have no downward relationships.
This query does what I want:
MATCH (t:type)-[:HAS]->(m:model)-[:HAS]-(r:region)-[:HAS]-(p:param)-[:HAS]-(i:init { value: 1613044800})-[init_has:HAS]-(u:{url: 'http://something2.png'})
DELETE init_has, u
WITH i,p,r,m,t
MATCH (i) WHERE NOT (i)-[:HAS]->()
DETACH DELETE i
WITH p,r,m,t
MATCH (p) WHERE NOT (p)-[:HAS]->()
DETACH DELETE p
WITH r,m,t
MATCH (r) WHERE NOT (r)-[:HAS]->()
DETACH DELETE r
WITH m,t
MATCH (m) WHERE NOT (m)-[:HAS]->()
DETACH DELETE m
WITH t
MATCH (t) WHERE NOT (t)-[:HAS]->()
DETACH DELETE t
But this query only deletes the first node in the in the WITH statement, i:
MATCH (t:type)-[:HAS]->(m:model)-[:HAS]-(r:region)-[:HAS]-(p:param)-[:HAS]-(i:init { value: 1613044800})-[init_has:HAS]-(u:{url: 'http://something2.png'})
DELETE init_has, u
WITH [i,p,r,m,t] AS parents
UNWIND parents AS parent
WITH parent
MATCH (parent) WHERE NOT (parent)-[:HAS]->()
DETACH DELETE parent
It leaves the node p, which does not have any downward relationships. Why are these queries different? Can I somehow modify the second query to correctly iterate through these nodes and delete them if they have no downward relationships?

Answer 1

I am not exactly sure what seems to be the problem. I can give you hint how you can improve your query a bit. When you want to do filtering on later steps, you don't have to use another MATCH statement. In your case:
MATCH (t:type)-[:HAS]->(m:model)-[:HAS]-(r:region)-[:HAS]-(p:param)-[:HAS]-(i:init { value: 1613044800})-[init_has:HAS]-(u:{url: 'http://something2.png'})
DELETE init_has, u
WITH [i,p,r,m,t] AS parents
UNWIND parents AS parent
WITH parent
WHERE NOT (parent)-[:HAS]->()
DETACH DELETE parent
I am not sure if this will solve your problem though. The query looks fine so it is hard to say whats wrong without an example.