I have a simple test graph that I run this query on:
MATCH p = (l)-[*1..1]->(start)-[*3..3]->(r) where id(start) = 1101 return l,r
This used to work in Neo4j 2.1, but after upgrading to 2.2, it no longer does, giving this error:
Don't know how to compare that. Left: [:has_participant[1027]{}] ($colon$colon); Right: :sampled[1025]{} (RelationshipProxy)
This query works:
MATCH p = (l)-[*1..1]->(start)-[*1..1]->(r) where id(start) = 1101 return l,start,r
Resulting in this visualisation:
The left node is (l), John node is (start) and the green nodes are (r).
If I double click on the green nodes, and then double-click on the nodes that appear, I can get to my intended (r) nodes, which are labelled as lanes:
Each "level" in this tree is joined with different relationships; 'has_participants' connects (l) to (start), and 'sampled' connects (start) to the green nodes. 'prepared' connects green to blue, and 'sequenced' connects blue to pink.
Given (start), how do I get to (l) and the 2 pink Lane nodes shown above without encountering the error? What I'm actually trying to do is a generic "give me descendant nodes of (start) that are at least 3 steps away", so I can't use knowledge of the sampled->prepared->sequenced relationship path.
Here's the result of EXPLAIN on the problem query:
This variant on the query works:
MATCH p = (l)-->(start)-[*3..3]->(r) where id(start) = 1101 return l,r
But why has my original query stopped working? What if I wanted to do 2..2 on the left?
Edit: in fact, even stranger is that these work:
MATCH p = (l)-[*0..1]->(start)-[*3..3]->(r) where id(start) = 1101 return l,r
MATCH p = (l)-[*1..2]->(start)-[*3..3]->(r) where id(start) = 1101 return l,r
Only 1..1 on the left fails.
