What is MySQL's explain execution plan

Explain syntax

EXPLAIN SELECT ...

Variant:

1. EXPLAIN EXTENDED SELECT ...

"Decompile" The execution plan into a SELECT statement, run show warnings to get the query statement optimized by the MySQL optimizer

2. EXPLAIN Partitions SELECT ...

Explain for partitioned tables

Information that the execution plan contains

Id

Contains a set of numbers that represent the order in which a SELECT clause or action table is executed in a query

Same ID, execution order from top to bottom

If it is a subquery, the ID number is incremented, the greater the ID value, the higher the priority, the more first executed

If the ID is the same, it can be considered a group, executed from top to lower, and in all groups, the greater the ID value, the higher the priority, the more first