成功回傳TRUE失敗回傳FALSE。
mysql_drop_db() attempts to drop
(remove) an entire database from the server associated with
the specified link identifier.
For downward compatibility
mysql_dropdb() can also be used. This is deprecated,
however.
注: The function mysql_drop_db() is deprecated. It is preferable to use mysql_query() to issue a SQL DROP DATABASE statement instead.
See also: mysql_create_db(),
mysql_query().