MySQL 8.4 Reference Manual Including MySQL NDB Cluster 8.4
DROP {DATABASE | SCHEMA} [IF EXISTS] db_name
      DROP DATABASE drops all tables in
      the database and deletes the database. Be
      very careful with this statement! To use
      DROP DATABASE, you need the
      DROP privilege on the database.
      DROP
      SCHEMA is a synonym for DROP
      DATABASE.
    
When a database is dropped, privileges granted specifically for the database are not automatically dropped. They must be dropped manually. See Section 15.7.1.6, “GRANT Statement”.
      IF EXISTS is used to prevent an error from
      occurring if the database does not exist.
    
      If the default database is dropped, the default database is unset
      (the DATABASE() function returns
      NULL).
    
      If you use DROP DATABASE on a
      symbolically linked database, both the link and the original
      database are deleted.
    
      DROP DATABASE returns the number of
      tables that were removed.
    
      The DROP DATABASE statement removes
      from the given database directory those files and directories that
      MySQL itself may create during normal operation. This includes all
      files with the extensions shown in the following list:
    
          .BAK
        
          .DAT
        
          .HSH
        
          .MRG
        
          .MYD
        
          .MYI
        
          .cfg
        
          .db
        
          .ibd
        
          .ndb
        
      If other files or directories remain in the database directory
      after MySQL removes those just listed, the database directory
      cannot be removed. In this case, you must remove any remaining
      files or directories manually and issue the
      DROP DATABASE statement again.
    
      Dropping a database does not remove any
      TEMPORARY tables that were created in that
      database. TEMPORARY tables are automatically
      removed when the session that created them ends. See
      Section 15.1.20.2, “CREATE TEMPORARY TABLE Statement”.
    
You can also drop databases with mysqladmin. See Section 6.5.2, “mysqladmin — A MySQL Server Administration Program”.