I'm trying to retrieve nodes where none of the relationships to that node have a specific property value. For example, I would like the query to return foo in the following example, because both relationships to foo have prop = false.
(bar0) -[{prop:false}]-> (foo) <-[{prop:false}]- (bar1)
On the other hand, I would like the query to return null in the following example, because a subset of the relationships to foo have prop = true.
(bar0) -[{prop:false}]-> (foo) <-[{prop:true}]- (bar1)
So far, I've tried:
MATCH (foo)-[r]-(bar)
WITH collect(r) as rs, foo, bar
WHERE NONE(r in rs WHERE r.prop = True)
UNWIND rs as r
RETURN foo, bar, r
However, this still returns foo, it just removes the relationship where prop = True.
I also tried using CASE, but run into the same problem.
MATCH (foo)-[r]-(bar)
WITH collect(r) as rs, foo
RETURN
CASE
WHEN ALL(r in rs WHERE r.prop=False)
THEN foo
ELSE null
END
Ideally, the query would also return nodes with no relationships as well, but I can also handle that with a separate query.
This query uses the EXISTS() function to avoid having to scan all relationships to every Foo node to find the ones of interest. It filters out a Foo node as soon as a true relationship is found.
MATCH (foo:Foo)
WHERE NOT EXISTS((foo)<-[{prop: true}]-())
MATCH (foo)<-[r]-(bar)
RETURN foo, bar, r
This query also uses a directional relationship, to conform to the stated data model.