使用py2neo时从python实现内的密码查询获取信息？

Question

I am implementing a search engine in python that will be connected to neo4j graph database. I have some data in the database and I want to get some information from the database using python code. I am connected with the database and I want to make a cypher query that will give me the prices that are lower than the average.

The first thing, I think it is good do to is to make a cypher query for the average price and then to use if(else) statements in python in order to differentiate between cheap and expensive.

 def cheap(self):
         query = '''
              MATCH (p:Price)-[:COSTS]-(s:Service)
              WITH avg(toFloat(p.monthly)) as {Average}, p.currency as {Currency}, s.service_name as {Service}
              Return Average,Currency, Service
               '''
          return cheap = graph.run(query, average= self.Average, currency= self.Currency, service_name=self.Service )

This python code is showing nothing. Does anyone have any idea on how to proceed??

Answer 1

One issue is that assignment in python doesn't return anything, so

return cheap = ...

will always return None . Try return graph.run(...) instead.

Also, the WITH statement in cypher is used to alias variables, not to filter them. Your cipher query should filter in a WHERE clause instead:

MATCH (p:Price)-[:COSTS]-(s:Service)
WITH avg(toFloat(p.monthly)) AS Average, p.currency AS Currency, s.service_name AS Service
WHERE Average = {Average}, Currency = {Currency}, Service = {Service}
RETURN Average,Currency, Service

Hopefully this helps!