为什么Neo4j查询没有在第一次查询中返回wright数据？

kiran 发表于 Dev

基兰

我有一个奇怪的问题，我无法理解Neo4j查询为什么返回不同的结果。

WITH shipper
MATCH (shipper)<-[:SHIPPED_BY]-(shipment:ActiveShipment)-[:SHIP_TO_CITY]->(toCity)
      <-[:HAS_CITY]-(toState:State), 
      **(veh:Vehicle)<-[:HAS_VEHICLE_TYPE]-(shipment)-[:SHIP_FROM_CITY]->(frmCity:City)
      <-[:HAS_CITY]-(frmState:State)**
RETURN shipment, toCity, frmCity, frmState, veh

退货

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但只要对查询稍作更改，便可以得到正确的结果：

WITH shipper
MATCH (shipper)<-[:SHIPPED_BY]-(shipment:ActiveShipment)-[:SHIP_TO_CITY]->(toCity)
      <-[:HAS_CITY]-(toState:State), 
     (veh:Vehicle)<-[:HAS_VEHICLE_TYPE]-(shipment)
**MATCH (shipment)-[:SHIP_FROM_CITY]->(frmCity:City)<-[:HAS_CITY]-(frmState:State)**
RETURN shipment, toCity, frmCity, frmState, veh

看起来像这样

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未退回的货物之间唯一的区别是，它们的toCity和fromCity相同。有人可以帮我了解我的第一个查询是什么问题吗？

更新

它很容易复制，

Create (st:State{Name:'ABC'})-[:HAS_CITY]->(c:City{Name:'XYZ'})<-[:SHIPPED_FROM]-(sh:Shipment{InternalId:1})-[:HAS_VEHICLE_TYPE]->(vh:Vehicle{Name:'Vheicle 1'}), (sh)-[:SHIPPED_TO]->(c)

现在，如果我添加此查询，它将失败

MATCH (shipment:Shipment)-[:SHIPPED_TO]->(toCity) <-[:HAS_CITY]-(toState:State), (veh:Vehicle)<-[:HAS_VEHICLE_TYPE]-(shipment)-[:SHIPPED_FROM]->(frmCity:City)<-[:HAS_CITY]-(frmState:State) RETURN shipment, toCity, frmCity, veh

我认为问题是，如果我删除该状态，则该状态将出现两次。

问候基兰

迈克尔·汉格

对同一个城市，同一个州有相同关系的权利，

因为这只是附加信息，所以您也可以将其拉到单独的match子句中。

像这儿：

MATCH (shipment:Shipment)-[:SHIPPED_TO]->(toCity)<-[:HAS_CITY]-(toState:State),(veh:Vehicle)<-[:HAS_VEHICLE_TYPE]-(shipment)-[:SHIPPED_FROM]->(frmCity:City)
MATCH (frmCity)<-[:HAS_CITY]-(frmState:State)
RETURN shipment, toCity, frmCity, veh

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