neo4j filter results from collect

Question

My problem is this, I have a query like this one:

MATCH (a:A),
(a)-[:relation]-(b:B)
RETURN {name: a.name, products: COLLECT(DISTINCT {productName: b.name, 
ident: b.identifier}) }

and I can't find a way to filter the result of 'products', for example, having the rows with the productName = 'pname1' contained in the array 'products':

row1: {name: 'name', products:[{name: 'pname1', ident: 'id1'}, {name: 'pname3', ident: 'id3'}] }
row2: {name: 'name2', products:[{name: 'pname2', ident: 'id2'}] }

The example above would only return the row1

Thank you in advance for your attention

Answer 1

The WITH clause is a very interesting thing with which the query can be splitted and the query results at this point can be saved to variables.

So, to only get the first row, the query would be

MATCH (a:A),
(a)-[:relation]-(b:B)
WITH a, COLLECT(DISTINCT {productName: b.name, ident: b.identifier}) as products
WHERE {productName: "pname1", ident:"id1"} in products
RETURN {name: a.name, products: products}

Edit:

The solution above compares the whole map which is a bit ugly if there are more properties. To only compare the productName the query is a bit more tricky:

MATCH (a:A),
(a)-[:relation]-(b:B)
WITH a, COLLECT(DISTINCT {productName: b.name, ident: b.identifier}) as products
UNWIND products as prows
WITH a, prows, products
WHERE prows.productName = "pname1"
RETURN {name: a.name, products: products}