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neo4jcypher

How to get nodes in neo4j based on property value

I have created some nodes with a property called: color. I haven't assigned any values to this property. Now I want to write a query to get all the nodes which have this property "NULL".

My query is this: 

  MATCH (n:Image) WHERE n.color='' RETURN n

But this returns nothing. How can I get all the nodes which belong to the label:Image and have the property:Color empty?

I also tried this with no luck:

MATCH (n:Image) WHERE n.color IS NULL RETURN n

Thanks D.

Solution

  • Null isn't a valid property value- if values are not assigned, or explicitly assigned null, then the property doesn't exist on the node.

    You can use either 

    MATCH (n:Image) where not(has(n.color)) return n

    to check if the property exists on the node or simply

    MATCH (n:Image) where n.color IS NULL

    Based on comments below, an empty String is not the same as a missing property/null value.