Reg：Neo4j显示空值

Question

我是Neo4j和图形数据库的新手。我正在尝试创建一个简单的图表数据库，但我的MATCH查询返回null值。如何避免编码中出现null或任何错误？

创建数据库

CREATE
  (d2:CorNode:course:dscor{Cors_Name:'DataScience_Sem2',Start_Date:'January2018',No_Students:[tointeger(10)]})-[:sem2dsrelation{Name:'Semester2',Cor_Name:'Data Science',A_Y:'AY2017-18',Cor_Node:'CMM534'}]->(Rob:FLNode:course:dscor{Name_F:'Rob Lothian', Role:'Leader',Mod_code:'CMM534'}),
  (d2)-[:sem2dsrelation{Name:'Semester2', Cor_Name:'Data Science',A_Y:'AY2017-18',Cor_Node:'CMM534'}]->(Eyad:FLNode:course:dscor{Name_F:'Eyad Elyan',Role:'Leader',Mod_code:'CMM534'}),
  (d2)-[:sem2dsrelation{Name:'Semester2', Cor_Name:'Data Science',A_Y:'AY2017-18',Cor_Node:'CMM507'}]->(David:FLNode:course:dscor{Name_F:'David Lonie', Role:'Leader', Mod_code:'CMM507'}),
  (d2)-[:sem2dsrelation{Name:'Semester2',Cor_Name:'Data Science', A_Y:'AY2017-18',Cor_Node:'CMM535'}]->(Rob),
  (d1:CorNode:course:dscor{Cors_Name:'DataScience_Sem1',Start_Date:'Septemer2017',No_Students:[tointeger(25)]})-[:sem1dsrelation{Name:'Semester1',Cor_Name:'Data Science',A_Y:'AY2017-18',Cor_Node:'CMM524'}]->(Rob),
  (d1)-[:sem1dsrelation{Name:'Semester1', Cor_Name:'Data Science',A_Y:'AY2017-18',Cor_Node:'CMM531'}]->(Eyad),
  (d1)-[:sem1dsrelation{Name:'Semester1', Cor_Name:'Data Science',A_Y:'AY2017-18',Cor_Node:'CMM510'}]->(Ines:FLNode:course:dscor{Name_F:'Ines Arana',Role:'Leader',Mod_code:'CMM510'})

查询数据库

MATCH (:dscor)-[ds1:sem1dsrelation{Name:'Semester1',Cor_Name:'Data Science'}]-(FLNode:dscor)
RETURN DISTINCT [FLNode.Name_F,ds1.Cor_Node]

Answer 1

你基本上有一个错字。在(FLNode:dscor)，＆＃34; FLNode＆＃34;正在使用变量名而不是标签。

要解决此问题，您需要为节点分配变量名称（例如x），确保将FLNode指定为标签（通过放置:前面的），然后在结果中使用x。像这样：

MATCH (:dscor)-[ds1:sem1dsrelation{Name:'Semester1',Cor_Name:'Data Science'}`]-(x:FLNode:dscor)
RETURN DISTINCT [x.Name_F,ds1.Cor_Node];