# Neo4j returning incorrect number of rows

**URL:** <https://community.neo4j.com/t/neo4j-returning-incorrect-number-of-rows/3655>\
**Category:** Procedures & APOC\
**Tags:** cypher\
**Created:** [December 6, 2018, 4:51am UTC](https://community.neo4j.com/t/neo4j-returning-incorrect-number-of-rows/3655 "2018-12-06T04:51:11Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![groverjatin17](https://sea1.discourse-cdn.com/flex021/user_avatar/community.neo4j.com/groverjatin17/32/2174_2.png) [@groverjatin17](https://community.neo4j.com/u/groverjatin17)\
**Post date:** [December 6, 2018, 4:51am UTC](https://community.neo4j.com/t/neo4j-returning-incorrect-number-of-rows/3655/1 "2018-12-06T04:51:11Z")

</div>

Hi All,

I am working on 1 Use case where we are merging all nodes(with 1 common property, such as all nodes with year= "2016" in Movie.csv table below) into 1 node where all the relationships are heading towards it rather than 3 different nodes.

For example:-  
I have 3 csv files with below type of data.

Actor.csv:-

| Actor Id | Name |
| --- | --- |
| 1 | Sam |

Movie.csv:-

| Movie Id | Movie Name | Year | Actor Id | Director Id |
| --- | --- | --- | --- | --- |
| 45 | Avengers | 2016 | 1 | 10 |
| 23 | Movie 2 | 2016 | 1 | 10 |
| 12 | Movie 3 | 2016 | 1 | 10 |

Director.csv:-

| Director ID | Director Name |
| --- | --- |
| 10 | Danny Morgan |

Now I merged all the Movie nodes into 1 node using `apoc.refractor.mergenodes` from APOC library.

Now when I request the data as a **TABLE** (not Graph) like:-

```auto
Match (a:Actor)-[:ACTED_IN]->(m:Movie)-[:DIRECTED_BY]->(d:Director)
return a.Name, m.Movie_Name,d.Director_Name

```

Ideally I should get only 3 rows with above mentioned info.  
But I get more rows than I am supposed to.

Please help me identify what is the reason and how to fix it.

(I think the issue is that each actor to movie realtionship is giving cartesian product with other 3 relationships of movie to director)  
NOTE:-I am using Neo4j Browser version 3.1.4

Thank you

---

<div class="post-metadata">

**Author:** ![andrew\_bowman](https://sea1.discourse-cdn.com/flex021/user_avatar/community.neo4j.com/andrew_bowman/32/73_2.png) [@andrew\_bowman](https://community.neo4j.com/u/andrew_bowman)\
**Post date:** [December 6, 2018, 4:55pm UTC](https://community.neo4j.com/t/neo4j-returning-incorrect-number-of-rows/3655/2 "2018-12-06T16:55:32Z")

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You're correct, if the merge resulted in multiple relationships between the same pairs of nodes (so 3 :ACTED\_IN relationships between the movie node and same actor, and 3 :DIRECTED\_BY relationships between the movie and same director) you'll end up with 9 rows.

We have a kb article on [understanding cardinality in Cypher](https://neo4j.com/developer/kb/understanding-cypher-cardinality/) which covers this.

The quick fix is to get DISTINCT nodes before you return:

```auto
MATCH (a:Actor)-[:ACTED_IN]->(m:Movie)-[:DIRECTED_BY]->(d:Director) 
WITH DISTINCT a, m, d
RETURN a.Name, m.Movie_Name,d.Director_Name

```

The better fix is to delete the duplicate relationships, since I don't think you need those in your graph:

```auto
MATCH (a:Actor)-[r:ACTED_IN]->(m:Movie)
WITH a, m, tail(collect(r)) as toDelete
WHERE size(toDelete) > 0
UNWIND toDelete
DELETE toDelete

```

and then a similar one for :DIRECTED\_BY.