Retrieving data from multiple nodes in neo4j Cypher

0
votes

I am trying to retrieve related data from multiple related nodes with the following cypher:

Match (n {email:{paramEmail}})-[*..3]-(m) Return n,m",
       { paramEmail: email})

The problem is if there are no existing relationship as yet then I get zero rows returned...user not found though the user(n) exist but at this point have no relationships. I still need the properties from the user(n) node so I have to make a separate call. Is there a query that would return n even though there was no relationship with m?

1
neo4jcypher

1 Answers

1
votes

Yes, match on the user with the email first, and then use an OPTIONAL MATCH for the rest:

MATCH (n {email:{paramEmail}})
OPTIONAL MATCH (n)-[*..3]-(m) Return n,m

Also, I'd advise you to use labels on your nodes. That way you could look up a :User by their email quickly (after creating an index on :User(email)). Right now the query has to scan all nodes of your graph to find those with the given email parameter.