Subtracting Cypher Queries

[Chris Bolton]

Okay here is my latest concoction: START n=node(127) MATCH(n)-[:friends]->(x) WITH n, collect(distinct x) as friends MATCH(n)-[:outer_only_friends]->(y) WITH n, collect(distinct y) as outer, friends RETURN collect(friends + outer) as stuff and it works! Is there any available syntax to subtract outer from friends? Effectively using a minus sign in place of the plus sign? I tried that. It throws a "Don't know how to subtract" error right now. Any help would be appreciated. Thanks. Chris

[Michael Hunger]

You would filter out the ones of the first that are part of the second with FILTER(x IN first : x IN second)

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[Peter Neubauer]

That one is nifty! Chris, if you can make a small domain example with this filter and describe it, I would love to add it to http://docs.neo4j.org/chunked/snapshot/data-modeling-examples.html . Maybe you cangive me a console.neo4j.org example with some text?

Cheers,

/peter neubauer

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[Chris Bolton]

Sounds good. I'll put something together and send it over. Chris --- On Sat, 8/18/12, Peter Neubauer <peter.n...@neotechnology.com> wrote:

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[Chris Bolton]

Okay, I've run into a couple problems 1) When I run this        RETURN collect (inner + outeronly + friends + outer) as total, filter(x in blocked + pending : x in total)")  I get this ... NativeException: org.neo4j.cypher.SyntaxException: blocked + pending expected to be of type IterableType<AnyType> but it is of type ScalarType from org/neo4j/cypher/internal/commands/Expression.scala:37:in `dependencies' I meant to mention that earlier. My query with the collections returns an interesting Java/Scala thing that took some Ruby magic to get to.  2) I attempted to recreate the Cypher query and sample data set for Peter in console but it didn't like me returning collections. http://console.neo4j.org/?id=ngb7xt As always any help would be greatly appreciated.

Chris --- On Sat, 8/18/12, Peter Neubauer <peter.n...@neotechnology.com> wrote:

From: Peter Neubauer <peter.n...@neotechnology.com> Subject: Re: [Neo4j] Subtracting Cypher Queries To: ne...@googlegroups.com Date: Saturday, August 18, 2012, 3:24 AM

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[Andres Taylor]

Hi Chris,

On Mon, Aug 20, 2012 at 5:03 PM, Chris Bolton <iknewt...@yahoo.com> wrote:

Okay, I've run into a couple problems 1) When I run this        RETURN collect (inner + outeronly + friends + outer) as total, filter(x in blocked + pending : x in total)")  I get this ... NativeException: org.neo4j.cypher.SyntaxException: blocked + pending expected to be of type IterableType<AnyType> but it is of type ScalarType from org/neo4j/cypher/internal/commands/Expression.scala:37:in `dependencies'

This problem has been fixed in snapshot. Does that work for you?

Andrés

 

[Andres Taylor]

Hi Chris,

Me and Peter worked over your examples, and this is what I suggest you use:

start n=node(1)  

match (n)-[:FRIENDS]->(x) with collect(distinct x) as friends, n

match (n)-[:FAMILY]->(y)  with collect(distinct y)+friends as total, n, friends

match (n)-[:BLOCKED]->(z) with collect(distinct z) as blocked, total  

return total, filter(x in total : not x in blocked) as newtotal

http://console.neo4j.org/r/amlaig

HTH,

Andrés