Adding scores from separate queries in Neo4j - database

Question

Say I have two tables as results of two separate Cypher queries:
First table:
login score
abc 10
def 20
And second table:
login score
abc 50
ghi 100
I need a table in which the scores for the logins that exist in both tables are summed, and for other logins, they are listed with the single score available for them.
login score
abc 60
def 20
ghi 100
Can you help with a Cypher query for this? What if I want to apply a custom aggregate function instead of simple summation?

Answer 1

This will not be super efficient if you have a large dataset, but something like the following will do the trick :
MATCH (c:Choice)
WITH collect(c.login) AS cset
MATCH (t:Thing)
WHERE NOT t.login IN cset
RETURN t.login AS login, t.score AS score
UNION ALL
MATCH (t:Thing)
WITH collect(t.login) AS tset
MATCH (c:Choice)
WHERE NOT c.login IN tset
RETURN c.login AS login, c.score AS score
UNION ALL
MATCH (c:Choice),(t:Thing {login: c.login})
RETURN c.login AS login, c.score + t.score AS score;
There may be more efficient ways to do this, but
First part gets you the scores for logins only in the Thing-nodes
Second part gets you the scores for logins only in the Choice-nodes
Third part sums the scores for logins present in both node types.
UNIONs link it all together.
Hope this helps,
Tom