Using matched node assignments in merge

Hi,

I’m trying to create a MERGE for a relationship after a MATCH statement, as described in MERGE: neo4j documentation. However I’m having issues re-using the node-assignments.

The query I’m trying to produce is:

MATCH (a:`Article` {`article_id`: '123456'}),(p:`Product` {`product_id`: '1234567'})
MERGE a-[r:BELONGS_TO]->p

However I seem to run into two issues; the first is a multiple match, I tried defining it as: p.MATCH.node(...).node(...) this outputs a non comma separated MATCH sequence which turns unusable. How would I achieve a comma separated MATCH sequence (as shown in the referenced documentation)?

Secondly I can’t seem to re-use the assigned node MATCH, in the above case assigned “a”:

p.MERGE.a.rel_out(labels="BELONGS_TO").p

Update What I’m trying to achieve is something similar to this:

MATCH(a:Article{product_id: '1234567'}), (p:Product{product_id: '1234567'})
MERGE (a)-[r:PART_OF]->(p)
RETURN a, r, p

Any ideas on this?

Thank you in advance

[emehrkay]

Edit: as you can see my return statement is wrong. You need to do it the way I described, with parens

p.RETURN(__.a, __.p, __.r)

[emehrkay]

The best way to handle this is to use the Anon class – __ and to execute MATCH with par’s

p.MATCH(__.node('a', 'Article', product_id='1234567'), __.node('p', 'Product', product_id='1234567'))

You can add parens to all of the statements and it will generate a list of comma-separated items https://github.com/emehrkay/Pypher#statement