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.
      Schema names are also available from the SHOW
      DATABASES statement. See
      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 a global privilege is considered a privilege for all
        databases, any global privilege enables a
        user to see all database names with SHOW
        DATABASES or by examining the
        INFORMATION_SCHEMA
        SCHEMATA table.