How to understand this query?

[lingvisa]

This is from the tutorial: :play https://guides.neo4j.com/got/01_eda.html. The "Game Of Thrones” dataset.

MATCH (c:Character)-->()
WITH c, count(*) AS num
RETURN min(num) AS min, max(num) AS max, avg(num) AS avg_characters, stdev(num) AS stdev

Result:

|min|max|avg_characters|stdev|
|---|---|---|---|
|1|148|6.578856152512995|14.160455871718893|

'-->': What does this do?
'num': Are arrays of what?

[Cobra]

Hello @lingvisa

It counts the relations by node c. One tip is to use RETURN to check what you get 😉
--> represents the relation.

Regards,
Cobra

[andrew_bowman · Accepted solution]

A bit more context, --> is shorthand for -[]->, so this is MATCHing on paths of a :Character node with a relationship (of any type) to any kind of node, then per character getting a count of rows. As a result per row we have each character and the number of relationships for that character (so num isn't an array, it's just an integer count, and we have a separate count per row/character). Then we apply aggregations over that count.