返回一个MATCH语句的多个关系计数 [英] Return multiple relationship counts for one MATCH statement

问题描述

我想做这样的事情:

MATCH (p:person)-[a:UPVOTED]->(t:topic),(p:person)-[b:DOWNVOTED]->(t:topic),(p:person)-[c:FLAGGED]->(t:topic) WHERE ID(t)=4 RETURN COUNT(a),COUNT(b),COUNT(c)

..但是当我应该得到2、1、1时，我得到了全部0个计数

..but I get all 0 counts when I should get 2, 1, 1

推荐答案

更好的解决方案是使用size，它可以大大提高查询的性能:

A better solution is to use size which improve drastically the performance of the query :

MATCH (t:Topic)
WHERE id(t) = 4
RETURN size((t)<-[:DOWNVOTED]-(:Person)) as downvoted,
       size((t)<-[:UPVOTED]-(:Person)) as upvoted,
       size((t)<-[:FLAGGED]-(:Person)) as flagged

如果您确定关系中的其他节点始终标有Person，则可以将它们从查询中删除，这样会再次更快

If you are sure that the other nodes on the relationships are always labelled with Person, you can remove them from the query and it will be a bit faster again

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