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nebula-graph

How to write a MATCH statement for bidirectional relationship patterns?

As shown in the figure, there are two nodes with bidirectional relationships in the pattern that needs to be matched.

graph model

MATCH 
(a)-[e1:trans]->(b)-[e2:trans]->(c),
(a)-[e1:trans]->(b)<-[e3:trans]->(c)
return a,b,c,e1,e2,e3

The statement is not valid and will result in a "duplicate identifier e1" error.

Can you sugguest how to write this MATACH statement for this pattern? Thanks!

Solution

  • I'm not sure about the Nebula Graph implementation, but with Cypher/openCypher in general, you cannot use the same relationship variable (e1 in this case) twice in a pattern. However, given you already have found b previously, your query can be simplified to

    MATCH (a)-[e1:trans]->(b)-[e2:trans]->(c),
      (b)<-[e3:trans]-(c)
RETURN a,b,c,e1,e2,e3