## 21. Example Query in Cypher (Neo4j)

```cypher
MATCH (a:ResourceFlow {type:'heat', direction:'output'})-[:LOCATED_AT]->(srcSite:Site),
      (b:ResourceFlow {type:'heat', direction:'input'})-[:LOCATED_AT]->(dstSite:Site),
      (srcSite)<-[:OPERATES_AT]-(srcBiz:Business),
      (dstSite)<-[:OPERATES_AT]-(dstBiz:Business)
WHERE distance(srcSite.location, dstSite.location) < 5000
  AND abs(a.quality.temperature_celsius - b.quality.temperature_celsius) < 10
  AND overlap(a.time_profile.availability, b.time_profile.availability) > 0.6
WITH srcBiz, dstBiz, srcSite, dstSite, a, b,
     (b.economic_data.cost_in - a.economic_data.cost_out - 0.0005*distance(srcSite.location, dstSite.location)) AS savings
WHERE savings > 0
RETURN srcBiz.name, dstBiz.name, srcSite.name, dstSite.name, savings
ORDER BY savings DESC LIMIT 20;
```

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