CODEWITHSUNDEEP
neo4jcypher
marhg
marhg

Reputation: 687

cypher return nodes located in the same place

Is a simple query, but i don't know which cypher operation or java collection would be useful to get the expected result.

So, again working with users assigned to a specific Taxi, where each user has a Grid destination (drop off).

First i returned the users assigned to a specific Taxi and same dropOff time:

MATCH (g:Grid)<-[d:DROP_OFF]-(u:User)-[rt:ASSIGNED]->(t:Taxi {name: 'Taxi1813'})
WHERE d.time = '04:38' 
RETURN u.name, g.name as LocationGrid

u.name           LocationGrid
UserTestSame     Grid1239
UserTestNew      Grid919
User177          Grid1239

I would like to add a condition to return the users located in the same Grid. The result set is not fixed; i may have n number f users.

Is there an easy way to do that, or should i use a collection in java to compare each Grid.

Thank you in advance

Upvotes: 0

Views: 53

Answers (2)

Mvde
Mvde

Reputation: 141

//just use the answer above me Also Neo4j has an option to use collect so the results come back in a list.

Match(n)-[]->(r) return n, collect (r) as collection

http://neo4j.com/docs/stable/query-aggregation.html#aggregation-collect

I think you should change your date time. Not in a string but more like yyyyMMddhhmmss so you can compare. Or any other way.

It would also be faster not to store it as a string.

Upvotes: 1

albertoperdomo
albertoperdomo

Reputation: 1949

You can use aggregate Cypher's built-in aggregate functions, such as collect:

MATCH (g:Grid)<-[d:DROP_OFF]-(u:User)-[rt:ASSIGNED]->(t:Taxi {name: 'Taxi1813'})
WHERE d.time = '04:38' 
RETURN g.name as LocationGrid, collect (u.name) as users

LocationGrid    users
Grid1239        [UserTestSame, User177]
Grid919         [UserTestNew]

Your query assumes that users assigned to the same taxi have the same drop off time? Seems confusing to me, but I might be missing something.

BTW, I don't think storing and matching the drop off time as a string is going to be very suitable for following reasons:

  • querying will be inefficient as you'll probably need to match both a date and a time string property
  • it doesn't allow for matching drop off times which are close

I'd recommend modelling the drop off time as a time tree. See following links for reference:

Upvotes: 1

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