Separate matches in one query

Question

I have nodes labeled 'Group' and only some of them have relationships with people. T

GroupA {}, GroupB{personA, personB}, GroupC{}

I want to get all the groups and members that have groups assigned to them but I can only figure out to get groups with members

Match (:Client {value:'1234'})-[:IDENTIFIES]->(a)<-[r:PART_OF*]-(b:Group)
<-[:BELONGS_TO]-(per:Person)

Even if I put a separate Match with a UNION I'm not able to get both the empty groups and membered groups. It says column names have to be same. I'm probably doing something wrong.

Any help?? Thanks!!

Answer 1

This query should do what you want. The per value in a result row will be null if the b Group has no Person belonging to it. You can play around with this query using this console link.

MATCH (:Client {value:'1234'})-[:IDENTIFIES]->(a)<-[r:PART_OF*]-(b:Group)
OPTIONAL MATCH (b)<-[:BELONGS_TO]-(per:Person)
RETURN DISTINCT a, b, per;

Answer 2

MATCH (c:Client {value: 1234})-[:IDENTIFIES]->(a)<-[r:PART_OF*]-(b:Group)<-[:BELONGS_TO]-             (per:Person), (g:Group) 
RETURN per, b, g 

This is assuming that you're ok with a duplication in the results in terms of the groups that are displayed. It also depends on how you want the results returned/displayed (e.g. you may want to use COLLECT). It might be a bit awkward to iterate through the "Member" results when each row contains all groups.

If you want just empty groups, maybe try something like:

MATCH (g:Group)
WHERE NOT g--()
RETURN g