Hi, thanks in advance for all the help offered at this community, it's really helpful.
I couldn't quite understand what's happening with the situation below.
Say there's a test data like this. Users can 'like' a certain project.
CREATE
(a:User),(b:User),(c:User),(p1:Project{id:1}),(p2:Project{id:2}),(p3:Project{id:3}),
(a)-[:LIKED]->(p3),(b)-[:LIKED]->(p3),(c)-[:LIKED]->(p3),
(a)-[:LIKED]->(p2),(b)-[:LIKED]->(p2)
I would like to get projects in order of liked counts. This is the query I wrote:
MATCH (p:Project)
OPTIONAL MATCH (p)-[l:LIKED]-(:User)
WITH count(l) as likedCount, p ORDER BY likedCount DESC
// perform some expensive task on p
RETURN p.id, likedCount
Now, since I am performing some expensive task with p,
I want to limit the number of projects to work on, with something like this.
MATCH (p:Project)
OPTIONAL MATCH (p)-[l:LIKED]-(:User)
WITH count(l) as likedCount, p ORDER BY likedCount DESC
WITH collect(p)[0..3] as projects, likedCount
UNWIND projects as p
// perform expensive task, but only to limited projects
RETURN p.id, likedCount
The result:
p.id likedCount
3 3
2 2
1 0
To paginate, for example excluding the most liked project, I would change [0..3] to [1..3] as such:
MATCH (p:Project)
OPTIONAL MATCH (p)-[l:LIKED]-(:User)
WITH count(l) as likedCount, p ORDER BY likedCount DESC
WITH collect(p)[1..3] as projects, likedCount
UNWIND projects as p
RETURN p.id, likedCount
Now I get this:
(no changes, no records)
Instead of getting 2 project rows, why did I get 0?
