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在获取两个值的总和并找到差异方面，我一直在与 Cypher 进行一些斗争。我有这两个查询，它们查找节点的发送总数和接收总数：

START addr = node(5)
MATCH addr <- [:owns] - owner - [to:transfers] -> receiver
RETURN SUM(to.value) AS Total_Sent

START addr = node(5)
MATCH addr <- [:owns] - owner <- [from:transfers] - sender
RETURN SUM(from.value) AS Total_Received

基本上我的问题是 - 我如何结合这两个单独的查询，以便我可以区分 Total_Sent 和 Total_Received？我尝试了多个起点，如下所示：

START sendAddr = node(5), receivedAddr = node(5)
MATCH sendAddr <- [:owns] - sendOwner - [to:transfers] -> receiver, receivedAddr <- [:owns] - receiveOwner <- [from:transfers] - sender
RETURN SUM(to.value) AS Total_Sent, SUM(from.value) AS Total_Received, SUM(to.value) - SUM(from.value) AS Balance

但 Total_Received 为空！对我来说，这看起来像是一个非常简单的用例——我到底做错了什么？

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1 回答 1

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您不能像这样将两个查询组合在一起。:)

为了解决这个问题，我建议您使用 WITH 将查询分成两部分，如下所示：

START addr = node(5)
MATCH addr <- [:owns] - owner - [to:transfers] -> receiver
WITH addr, SUM(to.value) AS Total_Sent

MATCH addr <- [:owns] - owner <- [from:transfers] - sender
WITH SUM(from.value) AS Total_Received, Total_Sent

RETURN Total_Received, Total_Sent, Total_Received - Total_Sent as Total_Balance

高温下，

安德烈斯

于 2012-09-04T19:03:01.663 回答