I am new to Neo4j and trying to create a query listing nodes and relationships into a graph with keyword as as below: ,如下所示:
(a) - [id:'0001', ref_id:null] -> (b) - [id:'0002', ref_id:'0001'] -> (c) - [id:'0003', ref_id:'0002'] -> (d)
Start Node will be (a) since it has relationship with id=0001
But the database also exists relationships which I don't want:
(a) - [id:'2001', ref_id:null] -> (b) - [id:'2002', ref_id:'2001'] -> (c)
(a) - [id:'3001', ref_id:null] -> (b) - [id:'3002', ref_id:'3001'] -> (c)
The result should only includes:
(a)-[0001]-(b)-[0002, 0001]-(c)-[0003,0002]-(d)
I know how to create this query in SQL database like Oracle and MySQL, I can use query with "where" condition. For example:
Select *
from table_a parent, (select * from table_a) child
where child.ref_id = parent.id
Then I can loop the result set in Java to find all relationships. But this is stupid.
I think the query should looks like:
Match (n)-[r:RELTYPE]->(m) WHERE {some conditions at here} RETURN n,r,m
Please help me, thank you!
Yufan
You could either use named relationships and filter in WHERE
clause:
match p = (a)-[r1:TYPE]->(b)-[r2:TYPE2]->(c)
where r1.id='0001' and r2.id='0002' and r2.ref_id='0001'
return p
Please note that properties having null value are not allowed in Neo4j. So the first relationship won't have a ref_id
.
For the above notation is a shortcut by putting the conditions into the match
:
match p = (a)-[r1:TYPE {id:'0001'}]->(b)-[r2:TYPE2 {id:'0002', ref_id:'0001'}]->(c)
return p
On a side note : I'm not sure if the way you're using id
and ref_id
in relationship properties is a good way to model your data. Maybe you can use more verbose relationship types - however without understanding the domain it's not really possible to give a good advice here.
I am using this Cypher query to find all neighbor with depth = 3.
MATCH (a)-[r1]-(b)-[r2]-(c)-[r3]-(n)
WHERE n.APPLE_ID='12345'
RETURN distinct n, distinct r3
Thanks
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