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Posted to dev@age.apache.org by GitBox <gi...@apache.org> on 2022/05/18 11:35:32 UTC

[GitHub] [incubator-age] jihot2000 opened a new issue, #218: some useful WHERE statements

jihot2000 opened a new issue, #218:
URL: https://github.com/apache/incubator-age/issues/218

   **Is your feature request related to a problem? Please describe.**
   I find it is difficult when I try to query a link list.
   I searched and found some useful cypher statements which works for Neo4j.
   
   **Describe the solution you'd like**
   
   - UNWIND a vertex list
   
   ```
   MATCH p=()-[]->()
   WITH nodes(p) AS a
   UNWIND a AS b
   RETURN b
   ```
   
   - WHERE not a relationship
   
   ```
   MATCH (head)-[:edge*]->()
   WHERE NOT ()-[:edge]->(head)
   RETURN head
   ```
   
   - list generation using IN
   
   ```
   MATCH p=()-[]->()
   WITH nodes(p) AS a
   RETURN [x IN a | x.name]
   ```
   
   


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[GitHub] [incubator-age] jihot2000 commented on issue #218: some useful cypher statements

Posted by GitBox <gi...@apache.org>.
jihot2000 commented on issue #218:
URL: https://github.com/apache/incubator-age/issues/218#issuecomment-1130122198

   I find 'WHERE NOT EXISTS' can do path pattern not match
   ```
   MATCH (head)-[:edge*]->()
   WHERE NOT EXISTS (()-[:edge]->(head))
   RETURN head
   ```


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[GitHub] [incubator-age] jrgemignani commented on issue #218: some useful cypher statements

Posted by GitBox <gi...@apache.org>.
jrgemignani commented on issue #218:
URL: https://github.com/apache/incubator-age/issues/218#issuecomment-1139180148

   List comprehension will be upcoming. Unwind should work, we will be looking into that.


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