<?php
    /**************************************************
        Convert WP Content encoding

        BASISSCRIPT: Markus Tacker <m@tacker.org>
        Modified:    Frank Bueltge <bueltge.de>
    ***************************************************/

    // New coding
    $new_encoding = 'UTF-8';

    // WordPress config
    require_once '../wp-config.php';

    // Connect DB
    $DBC = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD);
    mysql_select_db(DB_NAME, $DBC);

    $table = $wpdb->prefix.'comments';

    echo '<pre>';
        $result_data = mysql_query('SELECT * FROM ' . $table);
        echo $table . ' ';
        while ($data = mysql_fetch_assoc($result_data)) {
            $sql = 'UPDATE ' . $table;
            // Build set
            $set = array();
            foreach ($data as $key => $val) {
                $set[] = ek($key) . '=' . ev(mb_convert_encoding($data[$key], $new_encoding));
            }
            $sql .= ' SET ' . join(', ', $set);
            // Build where
            $where = array();
            foreach ($data as $key => $val) {
                if (!preg_match('/[0-9]+/', $val)) continue; // Use only numbers in where
                $where[] = ek($key) . '=' . ev($data[$key]);
            }
            $sql .= ' WHERE ' . join(' AND ', $where);
            $query_result = mysql_query($sql, $DBC);
            if (!$query_result) {
                die('Invalid query: ' . mysql_error());
            }
            echo '.';
            flush();
        }
        echo "\n";
    echo 'All done.&gt;/pre>';

    // Disconnect DB
    mysql_close($DBC);

    function ek($string)
    {
        global $DBC;
        return "`" . mysql_real_escape_string($string, $DBC) . "`";
    }

    function ev($string)
    {
        global $DBC;
        return "'" . mysql_real_escape_string($string, $DBC) . "'";
    }
?>