Neo4J 对过滤关系进行两次计数

Question

我有以下节点：

• 指导

• 操作

• 客户

我有以下关系

• 引导-[执行]->操作

• 操作 -[OPERATION_FOR]-> 客户

在

OPERATION_FOR

关系上，我有一个属性

guid

，它与

id

节点的

Guid

属性具有相同的值。

当我执行以下查询时

MATCH (guid:Guid{id:"005056AF0E7F1EECB0E4FCC33F085227"}) -[perform:PERFORMS]->(operation:Operation)
MATCH (operation) -[operationFor:OPERATION_FOR{guid:guid.id}]-> (customer:Customer)
RETURN operationFor,operation,customer

我预计有 5 个结果。 Graph 界面确实显示了 5 个关系，但实际上有 11 个关系

当我查看文本视图时，它显示 11 个条目，但有重复项。我发现了与此相关的其他问题，但这些问题的查询没有指定关系的方向，因此它被计算了两次。但我确实指定了方向，所以我不确定为什么会这样。

操作对于	操作	顾客
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T17:50:30",endTime: "2022-04-23T17:50:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "STORE"})	(:客户 {id: "Flexo"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "LOAD"})	(:客户 {id: "Elision"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T17:50:30",endTime: "2022-04-23T17:50:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T17:50:30",endTime: "2022-04-23T17:50:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})

当我执行

RETURN DISTINCT(operationFor),operation,customer

或执行以下查询时

MATCH (operation:Operation) -[operationFor:OPERATION_FOR{guid:"005056AF0E7F1EECB0E4FCC33F085227"}]-> (customer:Customer)
RETURN operationFor,operation,customer

我确实在表中得到了 5 个独特的条目。

操作对于	操作	顾客
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T17:50:30",endTime: "2022-04-23T17:50:36"}]	(:操作 {id: "SHIP"})	(:客户{id: "BP0103"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "STORE"})	(:客户 {id: "Flexo"})
[:OPERATION_FOR {guid: "005056AF0E7F1EECB0E4FCC33F085227",startTime: "2022-04-23T18:50:30",endTime: "2022-04-23T19:10:36"}]	(:操作 {id: "LOAD"})	(:客户 {id: "Elision"})

Answer 1

这是因为你们连续进行了两场比赛。 第一个 MATCH 将返回 5 行（Guid 执行的每个操作对应一行）。

第二场比赛将对第一场比赛的每一行进行一次。

只执行一次的两个操作也只会从第二场比赛中得到一个结果。但是，进行了三次的操作从第一场比赛中产生了三行，并且每个人都会在第二场比赛中获得三个命中。

因此最终结果有 3*3+2 = 11 行。

正如您自己建议的那样，解决方案是使用 DISTINCT。