MySQL 中的默认数据库介绍：https://dataedo.com/kb/databases/mysql/default-databases-schemas
| 默认数据库 | 官方文档 |
|---|---|
| information_schema | https://dev.mysql.com/doc/refman/8.0/en/information-schema.html |
| mysql | |
| performance_schema | https://dev.mysql.com/doc/refman/8.0/en/performance-schema.html |
| sys | https://dev.mysql.com/doc/refman/8.0/en/sys-schema.html |