我有一个DSL来查询RedisGraph,如下所示:
App::Graph.query(movie: { title: 'Matrix' }, country: { value: 'Italy' , value: 'Spain', value: 'Greece' })
它会生成这个密码查询:
MATCH (m:Movie)<-[:ACTED_IN]-(a:Actor)
WHERE m.title = 'Matrix'
WITH m, collect(a) as actors
WHERE 1 = 1
AND (movie)<-[:AVAILABLE_IN]-(:Country {value: 'Italy'})
AND (movie)<-[:AVAILABLE_IN]-(:Country {value: 'Spain'})
AND (movie)<-[:AVAILABLE_IN]-(:Country {value: 'Greece'})
RETURN actors, m
问:在某些情况下,Country
节点(例如西班牙)将没有edges
,因此目前上述cypher查询将正确地不返回任何结果。但是,有没有可能重写上面的查询,以便在Country
节点没有边的情况下忽略它,匹配并返回连接到剩余的初始定义的国家列表的节点,即意大利、希腊?
我已经尝试了很多选择,下面是最后一个,但没有找到实现这一点的方法
MATCH (m:Movie)<-[:ACTED_IN]-(a:Actor)
WHERE m.title = 'Matrix'
WITH m, collect(a) as actors
MATCH (m)<-[:AVAILABLE_IN]-(connected_countries)
WHERE connected_countries.value IN ['Italy', 'Spain', 'Greece']
WITH m, actors, collect(connected_countries.value) as relevant_countries
WHERE 1 = 1
AND ((movie)<-[:AVAILABLE_IN]-(:Country {value: 'Italy'}) AND IN relevant_countries)
AND ((movie)<-[:AVAILABLE_IN]-(:Country {value: 'Spain'}) AND IN relevant_countries)
AND ((movie)<-[:AVAILABLE_IN]-(:Country {value: 'Greece'}) AND IN relevant_countries)
RETURN actors, m
发布于 2021-11-15 05:07:39
请尝试:
MATCH (m:Movie {title:'Matrix'})
WITH m AS m
UNWIND ['Italy', 'Spain', 'Greece'] AS country_name
MATCH (:Country {value: country_name})-[:AVAILABLE_IN]->(m)<-[:ACTED_IN]-(a:Actor)
WITH m, collect(a) as actors
RETURN actors, m
https://stackoverflow.com/questions/69913773
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