(PHP 4, PHP 5)
mysql_list_dbs — List databases available on a MySQL server
This extension is deprecated as of PHP 5.5.0, and will be removed in the future. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
$link_identifier = NULL
  ] )Returns a result pointer containing the databases available from the current mysql daemon.
This function has been DEPRECATED as of PHP 5.4.0. Relying on this function is highly discouraged.
link_identifierThe MySQL connection. If the
link identifier is not specified, the last link opened by
mysql_connect() is assumed. If no such link is found, it
will try to create one as if mysql_connect() was called
with no arguments. If no connection is found or established, an
E_WARNING level error is generated.
   Returns a result pointer resource on success, or FALSE on
   failure. Use the mysql_tablename() function to traverse 
   this result pointer, or any function for result tables, such as 
   mysql_fetch_array().
  
Example #1 mysql_list_dbs() example
<?php
// Usage without mysql_list_dbs()
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$res = mysql_query("SHOW DATABASES");
while ($row = mysql_fetch_assoc($res)) {
    echo $row['Database'] . "\n";
}
// Deprecated as of PHP 5.4.0
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$db_list = mysql_list_dbs($link);
while ($row = mysql_fetch_object($db_list)) {
     echo $row->Database . "\n";
}
?>
The above example will output something similar to:
database1 database2 database3
Note:
For backward compatibility, the following deprecated alias may be used: mysql_listdbs()