Problem 1 - Statement

Given the graph below, construct a query to return the encircled sub-graph:

• return Application with property sealId=?
• return all ApplicationModules owned by Application
• return all APIs provided for each ApplicationModule
• return Request with max version property for each API

Problem 1 - Solutions

CQL v4.0 With APOC (without relationships)

MATCH (app:Application {sealId: 1})
OPTIONAL MATCH (app)<-[r0:IS_OWNED_BY]-(appMod:ApplicationModule)
OPTIONAL MATCH (appMod)-[r1:PROVIDES]->(api:Api)
WITH collect(DISTINCT app) AS apps, collect(DISTINCT appMod) AS appMods, collect(DISTINCT api) AS apis
UNWIND apis AS api
OPTIONAL MATCH (api)<-[r2:IS_OWNED_BY]-(request:Request)
WITH apps, appMods, apis, api, apoc.agg.maxItems(request, request.version).items AS requests
WITH apps, appMods, apis, requests
UNWIND requests AS request
RETURN apps, appMods, apis, collect(request) AS requests

CQL v4.0 With APOC (with relationships)

If you want to return the relationships between APIs and Request nodes, then use the following query below

MATCH (app:Application {sealId: 1})
OPTIONAL MATCH (app)<-[r0:IS_OWNED_BY]-(appMod:ApplicationModule)
OPTIONAL MATCH (appMod)-[r1:PROVIDES]->(api:Api)
WITH collect(DISTINCT app) AS apps, collect(DISTINCT appMod) AS appMods, collect(DISTINCT api) AS apis
UNWIND apis AS api
OPTIONAL MATCH (api)<-[r2:IS_OWNED_BY]-(request:Request)
WITH apps, appMods, apis, api, apoc.agg.maxItems(request, request.version).items AS requests, apoc.agg.maxItems(r2, request.version).items AS r2s
WITH apps, appMods, apis, requests, r2s
UNWIND requests AS request
UNWIND r2s AS r2
RETURN apps, appMods, apis, collect(request) AS requests, collect(r2) AS r2s

Problem 2 - Statement

Given the graph below, construct a query to return the encircled sub-graph:

• return Application with property sealId=?
• return all ApplicationModules owned by Application
• return all APIs provided for each ApplicationModule (return only the relationship with highest version property) ← ADDITIONAL CONSTRAINT
• return Request with max version property for each API

Problem 2 - Solution

CQL v4.0 With APOC

MATCH (app:Application {sealId: 1})
OPTIONAL MATCH (app)<-[r0:IS_OWNED_BY]-(appMod:ApplicationModule)
WITH collect(DISTINCT app) AS apps, collect(DISTINCT appMod) AS appMods, collect(DISTINCT r0) AS r0s
OPTIONAL MATCH (appMod)-[r1:PROVIDES]->(api:Api)
WITH apps, appMods, r0s, apoc.agg.maxItems(r1, r1.version).items AS grouped_r1s, api
UNWIND grouped_r1s AS r1
WITH apps, appMods, r0s, collect(DISTINCT r1) AS r1s, collect(DISTINCT api) AS apis
UNWIND apis AS api
OPTIONAL MATCH (api)<-[r2:IS_OWNED_BY]-(request:Request)
WITH apps, r0s, appMods, r1s, apis, api, apoc.agg.maxItems(r2, request.version).items AS r2s, apoc.agg.maxItems(request, request.version).items AS requests
WITH apps, r0s, appMods, r1s, apis, r2s, requests
UNWIND r2s AS r2
UNWIND requests AS request
RETURN apps, r0s, appMods, r1s, apis, collect(r2) AS r2s, collect(request) AS requests

Resources

• https://community.neo4j.com/t/cypher-query-for-return-node-which-some-field-max-some-field-value-out-of-a-group-of-nodes/9148/2