CODEWITHSUNDEEP
neo4jcypherneo4j-spatial
Mik378
Mik378

Reputation: 22171

Neo4j / Cypher / Traversing nodes having a specific label

I'm using Neo4j Spatial plugin.

Let's suppose this basic query:

START c = node:carslocation('withinDistance:[2.3725963,48.892067, 34.0]') 
RETURN c

It returns all the cars within 34 km.

What if I want to only retrieve race cars (using Labels).

Without Spatial I would do: 

MATCH (c:Race)
RETURN c

Now if I want all race cars within 34km, I would have:

START c = node:carslocation('withinDistance:[2.3725963,48.892067, 34.0]') 
MATCH (c:Race)
RETURN c

=> Cannot add labels or properties on a node which is already bound.
Indeed, c was already bound at the first line.

I don't want to have to do this: 

START c = node:carslocation('withinDistance:[2.3725963,48.892067, 34.0]') 
MATCH (cr:Race)
WHERE cr.id = c.id
RETURN cr

It would force me to open all nodes, to check for the equality... => bad performance especially when the query gets more complex ( even if id is indexed).

What could be an efficient solution?

UPDATE -------------------

Perhaps comparing nodes only is more efficient:

START c = node:carslocation('withinDistance:[2.3725963,48.892067, 34.0]') 
MATCH (cr:Race)
WHERE cr = c
RETURN cr

Is it?

Upvotes: 1

Views: 369

Answers (1)

Stefan Armbruster
Stefan Armbruster

Reputation: 39905

How about:

START c = node:carslocation('withinDistance:[2.3725963,48.892067, 34.0]') 
WHERE 'Race' in labels(c)
RETURN c

You basically lookup all nodes within the given region and then filter them if their labels contain Race.

Upvotes: 3

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