Cypher: filtering nodes if a relation exists

[Luanne Coutinho]

Hi,

How do you filter out nodes from the result of a cypher query based on whether a relation exists or not?

This is an example of what I was trying to do:

start n = node(13), interest=node(17)

match (n)<-[:knows|works_with]-(person)-[:friend]-(friend)-[:knows|works_with]-(friendProfile)

where not (friendProfile)-[:has]->(interest)<-[:has]->(n))

return friendProfile.name as name

I was trying to say- do not give me friendProfiles that have the same interest as the start node n.

Thanks

Luanne

[Peter Neubauer]

Luanne, is

http://docs.neo4j.org/chunked/snapshot/cypher-cookbook-similar-favorites.html
along these lines?

Cheers,

/peter neubauer

G:  neubauer.peter
S:  peter.neubauer
P:  +46 704 106975
L:   http://www.linkedin.com/in/neubauer
T:   @peterneubauer

If you can write, you can code - @coderdojomalmo
If you can sketch, you can use a graph database - @neo4j

[Josh Adell]

Maybe:

start n = node(13), interest=node(17)
match (n)<-[:knows|works_with]-(person)-[:friend]-(friend)-[:knows|

works_with]-(friendProfile)-[h?:has]->(interest)<-[:has]->(n)
where h is null
return friendProfile.name as name

-- Josh

[Luanne Coutinho]

Hi Peter,

That's what I thought- but if you take a look at the expression in my where clause, its more than 2 nodes with 1 relation:

start n = node(1), interest=node(7)

match (n)<-[:knows|works_with]-(person)-[:friend]-(friend)-[:knows|works_with]-(friendProfile)

where not (friendProfile)-[:has]->(interest)<-[:has]->(n)

return friendProfile.name as name

That seems to be the problem- on the console, I get "Error, expected return clause"

See http://tinyurl.com/6lgcqab

I don't have any interests there, but a fictitious interest of node 7 still produces that error with the query:

start n = node(1), interest=node(7)

match (n)<-[:knows|works_with]-(person)-[:friend]-(friend)-[:knows|works_with]-(friendProfile)

where not (friendProfile)-[:has]->(interest)<-[:has]->(n)

return friendProfile.name as name

Or I might have had too much cypher for today- let me know if you spot something silly.

Thanks

Luanne

[Michael Hunger]

Imho the where filtering can only check for direct relationships, not paths.

http://docs.neo4j.org/chunked/snapshot/query-where.html#where-filter-on-relationships

Michael

[Luanne Coutinho]

Josh, thanks- I will try that out.

-Luanne

[Andres Taylor]

On Tue, May 1, 2012 at 11:33 PM, Michael Hunger <michael...@neotechnology.com> wrote:

Imho the where filtering can only check for direct relationships, not paths.

This is exactly where sub-queries would be useful.

Andrés 

[Romiko Derbynew]

Hi Guys,


I think this feature will be useful, reason being, is you can have
more generic reltionship names e.g.

AuditCategoryNode->HAS_AUDIT->ClientNode<-IS_CLIENT
AuditCategoryNode->HAS_AUDIT->EmployeeNode<-IS_EMPLOYEE


So if I ran a report ONLY for audit nodes based on clients, it would
be nice to say get me all HAS_AUDIT where the node has an incoming
relationship IS_CLIENT.


Otherwise, it has to be done like this
AuditCategoryNode->HAS_CLIENT_AUDIT->ClientNode
AuditCategoryNode->HAS_EMPLOYEE_AUDIT->EmployeeNode

Thoughts guys? Would be nice to have a feature SIMILAR to gremlins
BACK statement, where you can traverse to CLIENT, go up to IS_CLIENT
and then kick a BACK step which filters out only CLIENTS :) I guess
this would have to be a subfilter, or perhaps it can currently be
done?





On May 2, 3:12 am, Andres Taylor <andres.tay...@neotechnology.com>
wrote:

> On Tue, May 1, 2012 at 11:33 PM, Michael Hunger <
>

[Andres Taylor]

On Fri, May 25, 2012 at 2:30 AM, Romiko Derbynew <rom...@gmail.com> wrote:

Hi Guys,


I think this feature will be useful, reason being, is you can have
more generic reltionship names e.g.

AuditCategoryNode->HAS_AUDIT->ClientNode<-IS_CLIENT
AuditCategoryNode->HAS_AUDIT->EmployeeNode<-IS_EMPLOYEE


So if I ran a report ONLY for audit nodes based on clients, it would
be nice to say get me all HAS_AUDIT where the node has an incoming
relationship IS_CLIENT.

Is something like this what you're after?

START  AuditCategoryNode=node(...)

MATCH AuditCategoryNode-[:HAS_AUDIT]->ClientNode

WHERE ClientNode<-[:IS_CLIENT]-()

RETURN ClientNode

Andrés