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Cypher query - check connection, if not, check another

I would like to check if a relationship exists from a node, and in case it is not found, then I want to check a different type of relationship with the same node.

Something like (a: Type) - [: relation1] - (b) if relation1 exists the query returns node b . If does not exist , then another relation of type (a: Type) - [: relation2] - (b) will be checked and returns node b .

I want to know how this can be written as a single cypher request. Any help would be greatly appreciated. Thank.

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2 answers


You can use COALESCE () to make a fallback selection if node in the first relation is null.



// after you've already matched to a
OPTIONAL MATCH (a)-[:relation1]-(b)
OPTIONAL MATCH (a)-[:relation2]-(c)
WITH a, COALESCE(b, c) as b // will use node c if b is null
...
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How about using UNION?

MATCH (a:Type)-[:relation1]-(b)
RETURN b
UNION
MATCH (a:Type)-[:relation2]-(b)
RETURN b


Hope this helps, Tom

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