Cypher返回重复数据

Question

我很难过，但我确信我错过了一些明显的东西。简而言之，我不知道为什么我的查询返回2倍我期望的值。

下面的屏幕截图显示了查询，它下面的查询结果，以及一些准确的基线数据（底部结果集）。

例如，团队B确实参与了4场比赛，得到10分，但顶部的第二个查询返回2次。

要跟进，这是我的玩具数据库：

// add constraint
CREATE CONSTRAINT ON (n:Team) ASSERT n.id IS UNIQUE;

// load the teams
LOAD CSV WITH HEADERS FROM "https://docs.google.com/spreadsheets/d/1QwXJE2qWVsejWeJGOouYxblNTox_Z9Ly5TWggzQNQVY/pub?gid=0&single=true&output=csv" AS row
WITH row
MERGE (t:Team {id:row.id, name:row.name});

// load the games
LOAD CSV WITH HEADERS FROM "https://docs.google.com/spreadsheets/d/1QwXJE2qWVsejWeJGOouYxblNTox_Z9Ly5TWggzQNQVY/pub?gid=33501648&single=true&output=csv" AS row
WITH row
CREATE (g:Game)
MERGE (h:Team {id:row.hometeam})
MERGE (a:Team {id:row.awayteam})
MERGE (a)-[:AWAY_TEAM {score:row.awayscore}]->(g)
MERGE (h)-[:HOME_TEAM {score:row.homescore}]->(g);

// Games played 
MATCH (t:Team)-[r]->(x:Game)
RETURN t.name, count(x) as games, sum(r.score) as for
ORDER BY games DESC

// the query in question which 2x's the results
MATCH (t1:Team)-[r1]->(g1:Game)
MATCH (g1)<-[r2]-(t2:Team)
RETURN t1.name, count(r1) as games, sum(r1.score) as for, sum(r2.score) as against
ORDER BY games DESC

以下是整个图表的视图，其中边缘的数字是团队在特定游戏中的分数

Answer 1

查询的问题在于，每个队伍在每场比赛中都会匹配两次。在这两个MATCH语句中：

MATCH (t1:Team)-[r1]->(g1:Game)
MATCH (g1)<-[r2]-(t2:Team)

每个团队都绑定到t1和t2。

要解决此问题，只需添加WHERE NOT t1=t2：

即可

MATCH (t1:Team)-[r1]->(g1:Game)
MATCH (g1)<-[r2]-(t2:Team) WHERE NOT t1=t2
RETURN t1.name, count(r1) as games, sum(r1.score) as for, sum(r2.score) as against
ORDER BY games DESC

此外，在您的LOAD CSV导入语句中，您应该使用toInt函数确保正确地转换整数（例如得分）：

LOAD CSV WITH HEADERS FROM "https://docs.google.com/spreadsheets/d/1QwXJE2qWVsejWeJGOouYxblNTox_Z9Ly5TWggzQNQVY/pub?gid=33501648&single=true&output=csv" AS row
WITH row
CREATE (g:Game)
MERGE (h:Team {id:row.hometeam})
MERGE (a:Team {id:row.awayteam})
MERGE (a)-[:AWAY_TEAM {score:toInt(row.awayscore)}]->(g)
MERGE (h)-[:HOME_TEAM {score:toInt(row.homescore)}]->(g);