> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/gridgain/gridgain-9/gridgain9-development/accessing-data/sql/overview.md).

# SQL Overview

GridGain 9 uses Apache Calcite as its SQL engine, providing distributed, transactional, standard-adherent SQL with advanced query optimization.

GridGain 9 uses Apache Calcite as an SQL engine of choice. Apache Calcite is a dynamic data management framework, which mainly serves for mediating between applications and one or more data storage locations and data processing engines. For more information on Apache Calcite, see the [Calcite documentation](https://calcite.apache.org/docs/).

GridGain 9 SQL engine has the following advantages:

* **SQL Optimized for Distributed Environments**: GridGain 9 distributed queries are not limited to a single map-reduce phase, allowing more complex data gathering;
* **Transactional SQL**: All tables in GridGain 9 support SQL transactions with transactional guarantees;
* **Cluster-wide System Views**: [System views](/docs/gridgain/gridgain-9/reference/monitoring/system-views.md) in GridGain 9 provide cluster-wide information, dynamically updated;
* **Multi-Index Queries**: With GridGain 9, you can perform queries that use multiple indexes at the same time to speed up queries;
* **Standard-Adherent SQL**: GridGain 9 SQL closely adheres to modern SQL standard;
* **Improved optimization algorithms**: SQL in GridGain 9 optimizes queries by repeatedly applying planner rules to a relational expression;
* **High overall performance**: GridGain 9 offers high levels of execution flexibility, as well as high efficiency in terms of both memory and CPU consumption.

## See Also

* [Create Tables and Query Data With SQL](/docs/gridgain/gridgain-9/gridgain9-get-started/learning-paths/distributed-sql-foundations/query-music-store-sql.md)