A schema is a database, so the SCHEMATA table provides information about databases.
The SCHEMATA table has these columns:
CATALOG_NAME
The name of the catalog to which the schema belongs. This value is always def.
SCHEMA_NAME
The name of the schema.
DEFAULT_CHARACTER_SET_NAME
The schema default character set.
DEFAULT_COLLATION_NAME
The schema default collation.
SQL_PATH
This value is always NULL.
DEFAULT_ENCRYPTION
The schema default encryption. This column was added in MySQL 8.0.16.
Schema names are also available from the SHOW DATABASES statement. See Section 13.7.7.14, “SHOW DATABASES Statement”. The following statements are equivalent:
SELECT SCHEMA_NAME AS `Database` FROM INFORMATION_SCHEMA.SCHEMATA [WHERE SCHEMA_NAME LIKE 'wild'] SHOW DATABASES [LIKE 'wild']
You see only those databases for which you have some kind of privilege, unless you have the global SHOW DATABASES privilege.
Because any static global privilege is considered a privilege for all databases, any static global privilege enables a user to see all database names with SHOW DATABASES or by examining the SCHEMATA table of INFORMATION_SCHEMA, except databases that have been restricted at the database level by partial revokes.
The SCHEMATA_EXTENSIONS table augments the SCHEMATA table with information about schema options.