Cypher query with diverging paths

Question

I would like to query for the following subgraph in my Neo4J database:

(a)-->(b)-->(c)-->(d)
       |
       | -->(e)

Note: a, b, c, d, e are attribute values (non-unique values) for each of the nodes. There are thousands for these nodes with similar attribute values (a to e) but they are randomly connected to one another.

How can I write the Cyper query to specifically find the particular subgraph (akin to subgraph isomorphism problem) I seek and return (a)? I've tried the following Cyper query but other subgraphs pop up:

START n1=node:SomeIndex(AttrVal="a")
MATCH n1-[]->n2-[]->n3-[]->n4
WHERE n2.AttrVal="b" AND n3.AttrVal="c" and n4.AttrVal="d"
WITH  n1, n2
MATCH n2-[]->n5
WHERE n5.AttrVal="e"
RETURN n1

Am I using the WITH and 2nd MATCH clause wrongly?

Thanks!

Could you describe in natural language what your query should really do? Your cypher statement does not fit the ascii art graph since you match for n1-->n5 in Cypher but b is connected to e in ascii. — Stefan Armbruster
Stefan - Updated the code example to match the ASCII graph correctly. I'm essentially trying to do subgraph matching here, in a database full of all these node with various attribute values. — Victor Neo

Stefan Armbruster Stefan Armbruster · Accepted Answer · 2013-07-04T20:12:46

You can use the comma to combine multiple paths in a single match clause:

START n1=node:SomeIndex(AttrVal="a")
MATCH n1-[]->n2-[]->n3-[]->n4, n2-[]->n5
WHERE n2.AttrVal="b" AND n3.AttrVal="c" and n4.AttrVal="d" and n5.attrVal='e'
RETURN n1

Side note 1: you can also refactor the statement like this:

START n1=node:SomeIndex(AttrVal="a"), n2=node:SomeIndex(AttrVal="b")
n3=node:SomeIndex(AttrVal="c"), n4=node:SomeIndex(AttrVal="d"),
n5=node:SomeIndex(AttrVal="e")
MATCH n1-[]->n2-[]->n3-[]->n4, n2-[]->n5
RETURN n1

Depending on the structure of your graph the second might be faster.

Side note 2: When matching an arbitrary relationship type as you did in n1-[]->n2 you can use a shorter and more readable notation: n1-->n2

Cypher query with diverging paths

1 Answers