protected function _stripQuoted($sql)
    {
        // get the character for delimited id quotes,
        // this is usually " but in MySQL is `
        $d = $this->_adapter->quoteIdentifier('a');
        $d = $d[0];

        // get the value used as an escaped delimited id quote,
        // e.g. \" or "" or \`
        $de = $this->_adapter->quoteIdentifier($d);
        $de = substr($de, 1, 2);
        $de = str_replace('\\', '\\\\', $de);

        // get the character for value quoting
        // this should be '
        $q = $this->_adapter->quote('a');
        $q = $q[0];

        // get the value used as an escaped quote,
        // e.g. \' or ''
        $qe = $this->_adapter->quote($q);
        $qe = substr($qe, 1, 2);
        $qe = str_replace('\\', '\\\\', $qe);

        // get a version of the SQL statement with all quoted
        // values and delimited identifiers stripped out
        // remove "foo\"bar"
        $sql = preg_replace("/$q($qe|\\\\{2}|[^$q])*$q/", '', $sql);
        // remove 'foo\'bar'
        if (!empty($q)) {
            $sql = preg_replace("/$q($qe|[^$q])*$q/", '', $sql);
        }

        return $sql;
    }