neo4j过滤器来自collect

Question

我的问题是这个，我有一个像这样的查询：

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

我无法找到过滤'产品'结果的方法，例如，数组'products'中包含productName ='pname1'的行：

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

上面的例子只会返回row1

提前感谢您的关注

Answer 1

WITH 子句是一个非常有趣的事情，可以将查询拆分，此时的查询结果可以保存到变量中。

因此，要仅获取第一行，查询将为

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}

修改

上面的解决方案比较整个地图，如果有更多属性，这有点难看。仅比较productName查询有点棘手：

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}