Cypher Neo4j ORDER BY DESC查询

Question

我想按降序排列COUNT（Movie.title）。 但它给出了一个错误。 这是查询。

MATCH (Movie {genre:"Action"})<-[:ACTS_IN]-(Person)
                 "RETURN Person.name, Movie.genre,  COUNT(Movie.title)"
                 "ORDER BY COUNT(Movie.title) DESC"
                 "LIMIT 100";

谢谢！

Answer 1

您可以使用此查询：

MATCH (movie:Movie {genre:"Action"})<-[:ACTS_IN]-(person:Person)
RETURN person.name, movie.genre,  COUNT(distinct movie.title) AS cnt
ORDER BY cnt DESC
LIMIT 100

Answer 2

返回错误是因为您无法立即在Cypher中按聚合顺序排序。 要按任何聚合订购，您需要使用WITH运算符。

所以你的查询应该是（假设你想列出每个类型的每个演员的标题）：

MATCH (Movie {genre:"Action"})<-[:ACTS_IN]-(Person)
RETURN Person.name, Movie.genre,  COUNT(Movie.title)
WITH Person.name AS name, Movie.genre AS genre, COLLECT(Movie.title) AS titles
RETURN name, genre, titles
ORDER BY LENGTH(titles) DESC
LIMIT 100

限制100现在已经改变了它的行为，因此您可能希望将其移动到查询中：

MATCH (Movie {genre:"Action"})<-[:ACTS_IN]-(Person)
RETURN Person.name, Movie.genre,  COUNT(Movie.title)
WITH Person, Movie
LIMIT 100
WITH Person.name AS name, Movie.genre AS genre, COLLECT(Movie.title) AS titles
RETURN name, genre, titles
ORDER BY LENGTH(titles) DESC

除此之外：为了使您的查询运行良好，您应该在Movie.genre属性上有一个索引，您应该为Movie和Person引入标签。