PHP如何列出MySQL中所有数据库

<?php
define( 'NL', "\n" );
define( 'TB', ' ' );
// connecting to MySQL.
$conn = @mysql_connect( 'localhost', 'username', 'password' )
    or die( mysql_errno().': '.mysql_error().NL );
// attempt to get a list of MySQL databases
// already set up in my account. This is done
// using the PHP function: mysql_list_dbs()
$result = mysql_list_dbs( $conn );
// Output the list
echo '<ul class="projects">'.NL;
 ///* USING: mysql_fetch_object()
 // ---------------------------
 while( $row = mysql_fetch_object( $result ) ):
  echo TB.'<li>'.$row->Database.'</li>'.NL;
 endwhile;
 //*/
 /* USING: mysql_fetch_row()
 // ------------------------
 while( $row = mysql_fetch_row( $result ) ):
  echo TB.'<li>'.$row[0].'</li>'.NL;
 endwhile;
 //*/
 /* USING: mysql_fetch_assoc()
 // --------------------------
 while( $row = mysql_fetch_assoc( $result ) ):
  echo TB.'<li>'.$row['Database'].'</li>'.NL;
 endwhile;
 //*/
echo '</ul>'.NL;
// Free resources / close MySQL Connection
mysql_free_result( $result );
mysql_close( $conn );  
?>