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Functions Overview

MonkDB function surface includes:

  • Scalar functions
  • Aggregate functions
  • Table functions
  • User-defined functions (UDFs)

Function classes

Scalar functions

Used in projection, filters, expressions, computed columns.

Examples:

SELECT lower(name), date_part('day', current_timestamp), array_length(tags, 1)
FROM doc.users;

Aggregate functions

Used with grouping/aggregation pipelines.

Examples: count, sum, avg, min, max, percentile families.

Table functions

Return row sets and are used in FROM.

Examples in graph domain:

  • graph_neighbors(...)
  • traverse(...)

UDFs

Defined via CREATE FUNCTION and callable like built-in functions.

Function discovery

Use runtime catalog queries to inspect the exact function set in your running build:

SELECT proname, oid::int
FROM pg_catalog.pg_proc
ORDER BY proname;

For workflows and examples, continue with: