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Differences in Cypher implementations

Although we try to implement the openCypher query language as close to the language reference as possible, we had to make some changes to enhance the user experience.

Unicode codepoints in string literals​

Use \u followed by 4 hex digits in string literals for UTF-16 codepoint and \U with 8 hex digits for UTF-32 codepoint in Memgraph.

Difference from Neo4j's Cypher implementation​

The openCypher initiative stems from Neo4j's Cypher query language. Following is a list of the most important differences between Neo's Cypher and Memgraph's openCypher implementation for users already familiar with Neo4j. Other differences might not be documented here (especially subtle semantic ones).

Unsupported constructs​

  • Stored procedures.
  • shortestPath and allShortestPaths functions. They can be expressed using Memgraph's depth-first search and all shortest paths expansion syntax. Among Memgraph's built in algorithms are also breadth-first search and weighted shortest path.
  • Patterns in expressions. For example, Memgraph doesn't support size((n)-->()). Most of the time, the same functionalities can be expressed differently in Memgraph using OPTIONAL expansions, function calls etc. You can check out this example.
  • Map projections such as MATCH (n) RETURN n {.property1, .property2}.

Unsupported functions​

General purpose functions:

  • exists(n.property) - This can be expressed using n.property IS NOT NULL.
  • length() is named size() in Memgraph.

Mathematical functions:

  • percentileDisc()
  • stDev()
  • point()
  • distance()
  • degrees()

List functions:

  • none()

Patterns in expressions​

Patterns in expressions are supported in Memgraph in particular functions, like exists(pattern). In other cases, Memgraph does not yet support patterns in functions, e.g. size((n)-->()). Most of the time, the same functionalities can be expressed differently in Memgraph using OPTIONAL expansions, function calls, etc.