W3cubDocs

/MariaDB

Optimizations for Derived Tables

Derived tables are subqueries in the FROM clause. Prior to MariaDB 5.3/MySQL 5.6, they were too slow to be usable. In MariaDB 5.3/MySQL 5.6, there are two optimizations which provide adequate performance:

Title Description
Condition Pushdown into Derived Table Optimization If a query uses a derived table (or a view), the first action that the que...
Derived Table Merge Optimization MariaDB 5.3 introduced the derived table merge optimization
Derived Table with Key Optimization Since MariaDB 5.3, the optimizer can create an index and use it for joins with other tables
Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.

© 2019 MariaDB
Licensed under the Creative Commons Attribution 3.0 Unported License and the GNU Free Documentation License.
https://mariadb.com/kb/en/optimizations-for-derived-tables/