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# SPARQL Cheatsheet

## Unique Features
- Query language for retrieving data from RDF graphs
- Supports graph pattern matching and filtering
- Can be used to query data from the semantic web
- Based on RDF and RDF Schema standards
- Can be extended with user-defined functions and operators

## Basic Query Structure

SELECT ?variable_name

WHERE {

// Query pattern

}

## Triple Patterns

subject_predicate_object

## Query Modifiers

LIMIT limit_value

OFFSET offset_value

ORDER BY variable_name

## Filtering

FILTER condition

## Optional Patterns

OPTIONAL {

// Optional pattern

}

## Union

{

// Pattern 1

}

UNION {

// Pattern 2

}

## Grouping and Aggregation

SELECT ?variable_name (aggregate_function(?variable_name) AS ?aggregate_variable_name)

WHERE {

// Query pattern

}

GROUP BY ?variable_name

## User-Defined Functions

PREFIX my_functions: <http://example.org/my_functions#>

SELECT ?variable_name

WHERE {

// Query pattern

FILTER my_functions:function_name(?variable_name)

}

## Resources
- [SPARQL 1.1 Query Language](https://www.w3.org/TR/sparql11-query/)
- [SPARQL by Example](https://www.cambridgesemantics.com/blog/semantic-university/sparql-by-example/)
- [Apache Jena](https://jena.apache.org/) (Java framework for working with RDF and SPARQL)
- [RDFLib](https://rdflib.readthedocs.io/) (Python library for working with RDF and SPARQL)