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# <a id="Introduction">1. Introduction</a><font size="3"/>

This document is intended as a reference guide to the full syntax and semantics of
AsterixDB's query language, a SQL-based language for working with semistructured data.
The language is a derivative of SQL++, a declarative query language for JSON data which
is largely backwards compatible with SQL.
SQL++ originated from research in the FORWARD project at UC San Diego, and it has
much in common with SQL; some differences exist due to the different data models that
the two languages were designed to serve.
SQL was designed in the 1970's for interacting with the flat, schema-ified world of
relational databases, while SQL++ is much newer and targets the nested, schema-optional
(or even schema-less) world of modern NoSQL systems.

In the context of Apache AsterixDB, the query language is intended for working with the Asterix Data Model
([ADM](../datamodel.html)), a data model based on a superset of JSON with an enriched and flexible type system.
New AsterixDB users are encouraged to read and work through the (much friendlier) guide
"[AsterixDB 101: An ADM and SQL++ Primer](primer-sqlpp.html)" before attempting to make use of this document.
In addition, readers are advised to read through the [Asterix Data Model (ADM) reference guide](../datamodel.html)
first as well, as an understanding of the data model is a prerequisite to understanding the query language.

In what follows, we detail the features of the query language in a grammar-guided manner.
We list and briefly explain each of the productions in the query grammar, offering examples
(and results) for clarity.

