public function from($table, $selectFields = array('*'))
    {
    	list($tableName, $tableAlias) = $this->tableProcess($table);
        $this->fromTable[$tableAlias] = $tableName;
        if (empty($selectFields)) {
            return $this;
        }
        if ($this->queryType == self::QUERYTYPE_SELECT) {
            $this->fields[$tableAlias] = $this->fieldProcess($tableAlias, $selectFields);
        } else {
            $this->fields[$tableAlias] = $selectFields;
        }
        return $this;
    }