neo4j-cypher-guide

Neo4j Modern Cypher Query Guide

This skill helps generate Neo4j Cypher read queries using modern syntax patterns and avoiding deprecated features. It focuses on efficient query patterns for graph traversal and data retrieval.

Quick Compatibility Check

When generating Cypher queries, immediately avoid these REMOVED features:

• ❌ id() function → Use elementId()
• ❌ Implicit grouping keys → Use explicit WITH clauses
• ❌ Pattern expressions for lists → Use pattern comprehension or COLLECT subqueries
• ❌ Repeated relationship variables → Use unique variable names
• ❌ Automatic list to boolean coercion → Use explicit checks

Core Principles for Query Generation

1. Use modern syntax patterns - QPP for complex traversals, CALL subqueries for complex reads
2. Optimize during traversal - Filter early within patterns, not after expansion
3. Always filter nulls when sorting - Add IS NOT NULL checks for sorted properties
4. Explicit is better than implicit - Always use explicit grouping and type checking

Critical Sorting Rule

ALWAYS filter NULL values when sorting:

// WRONG - May include null values
MATCH (n:Node)
RETURN n.name, n.value
ORDER BY n.value

// CORRECT - Filter nulls before sorting
MATCH (n:Node)
WHERE n.value IS NOT NULL
RETURN n.name, n.value
ORDER BY n.value

Query Pattern Selection Guide

For Simple Queries

Use standard Cypher patterns with modern syntax:

MATCH (n:Label {property: value})
WHERE n.otherProperty IS :: STRING
RETURN n

For Variable-Length Paths

Consider Quantified Path Patterns (QPP) for better performance:

// Instead of: MATCH (a)-[*1..5]->(b)
// Use: MATCH (a)-[]-{1,5}(b)

// With filtering:
MATCH (a)((n WHERE n.active)-[]->(m)){1,5}(b)

For Aggregations

Use COUNT{}, EXISTS{}, and COLLECT{} subqueries:

MATCH (p:Person)
WHERE count{(p)-[:KNOWS]->()} > 5
RETURN p.name, 
       exists{(p)-[:MANAGES]->()} AS isManager

For Complex Read Operations

Use CALL subqueries for sophisticated data retrieval:

MATCH (d:Department)
CALL (d) {
  MATCH (d)<-[:WORKS_IN]-(p:Person)
  WHERE p.salary IS NOT NULL  // Filter nulls
  WITH p ORDER BY p.salary DESC
  LIMIT 3
  RETURN collect(p.name) AS topEarners
}
RETURN d.name, topEarners