MysqliDb::conditionToSql PHP Method

    private function conditionToSql($operator, $val)
    {
        switch (strtolower($operator)) {
            case 'not in':
            case 'in':
                $comparison = ' ' . $operator . ' (';
                if (is_object($val)) {
                    $comparison .= $this->_buildPair("", $val);
                } else {
                    foreach ($val as $v) {
                        $comparison .= ' ?,';
                        $this->_bindParam($v);
                    }
                }
                $this->_query .= rtrim($comparison, ',') . ' ) ';
                break;
            case 'not between':
            case 'between':
                $this->_query .= " {$operator} ? AND ? ";
                $this->_bindParams($val);
                break;
            case 'not exists':
            case 'exists':
                $this->_query .= $operator . $this->_buildPair("", $val);
                break;
            default:
                if (is_array($val)) {
                    $this->_bindParams($val);
                } else {
                    if ($val === null) {
                        $this->_query .= $operator . " NULL";
                    } else {
                        if ($val != 'DBNULL' || $val == '0') {
                            $this->_query .= $this->_buildPair($operator, $val);
                        }
                    }
                }
        }
    }