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
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