This document summarizes SPARQL, the SPARQL query language used for querying and retrieving data stored in RDF format. It discusses key concepts such as RDF, terms, syntax, patterns, and constraints. RDF represents information as subject-predicate-object triples that can be queried using SPARQL. SPARQL allows constructing basic and complex graph patterns to match against the RDF graph. It also supports value filters, ordering, pagination and other solution modifiers. The document provides examples of SPARQL queries to retrieve data from RDF graphs based on different conditions and constraints.