Cypher: Extract unique values from collection

问题

I have

MATCH (x)-[rels*]->(y)
RETURN extract( r in rels | r.property) as collected

where collected is a collection of properties of all relationships along the path, such as [null, 4, null, 4] or [1, 3, 3, 1].

How can I further extract from collected only its unique values? For example, [null, 4, null, 4] would change into [null, 4]

回答1:

try this instead:

MATCH (x)-[rels*]->(y)
UNWIND rels AS rel
RETURN COLLECT( distinct rel.property) AS collected

来源：https://stackoverflow.com/questions/26634802/cypher-extract-unique-values-from-collection