在 Cypher 中有多个 OPTIONAL MATCH

Question

I'm looking to form a query what should match on at least one of the OPTIONAL MATCH. In this form it would return a result even when none of the OPTIONAL MATCH, which is not what I desire.

MATCH (media:Media)-[rr:HAS]-(ad:Ad) OPTIONAL MATCH (media)--(word:Word) WHERE word.value IN ['thing'] OPTIONAL MATCH (media) WHERE media.description CONTAINS 'something' RETURN media, collect(DISTINCT word) as word, collect(DISTINCT ad) as ad

Answer 1

UNION would be a better fit in this case. The only caveat is that you return columns with the same alias from each part of the union.

MATCH (media:Media)-[rr:HAS]-(ad:Ad) 
MATCH (media)--(word:Word) WHERE word.value IN ['thing']
RETURN media, collect(DISTINCT word) as things
UNION 
MATCH (media:Media)-[rr:HAS]-(ad:Ad) 
MATCH (media) WHERE media.description CONTAINS 'something'
RETURN media, collect(DISTINCT ad) as things

This would produce zero results if neither part matches, and at least one if either matches.