MySQL 8 Administrator???s Guide

Query execution plan

The MySQL optimizer considers optimization techniques to efficiently perform the lookups involved in the query, depending on the details of the tables, columns, and indexes, and the conditions in the WHERE clause. A query can also be performed without reading all the rows on a huge table. An SQL join can also be performed without comparing every combination of rows. A query execution plan is a set of operations that the MySQL optimizer chooses to perform the most efficient query. It is also known as the EXPLAIN plan. As an administrator, the goal is to recognize the aspects of the query execution plan which indicate if a query is optimized.

The EXPLAIN statement is used to determine the query execution plan. The following ...