Neo4j: how do I delete all duplicate relationships in the database through cypher?

Question

I have a huge database with a ton of nodes (10mil+). There is only one type of relationship in the whole database. However, there are a ton of nodes that have duplicated rel

Answer 1

This is a version of the accepted answer that has been fixed (by inserting the WITH rr clause) to work with more recent neo4j versions, and which should be faster (since it only creates the new TAIL list when needed):

MATCH (a)-[r]->(b)
WITH a, b, COLLECT(r) AS rr
WHERE SIZE(rr) > 1
WITH rr
LIMIT 100000
FOREACH (r IN TAIL(rr) | DELETE r);

[UPDATE]

If you only want to delete duplicate relationships with the same type, then do this:

MATCH (a)-[r]->(b)
WITH a, b, TYPE(r) AS t, COLLECT(r) AS rr
WHERE SIZE(rr) > 1
WITH rr
LIMIT 100000
FOREACH (r IN TAIL(rr) | DELETE r);