src/Service/DB/Select.php
public function execute()
    {
        list($sql, $params) = $this->compile();

        return $this->adapter->execute($sql, $params);
    }
public function execute()
    {
        list($sql, $params) = $this->compile();

        return $this->adapter->execute($sql, $params);
    }
执行查询，返回查询结果句柄对象

@return \Owl\Service\DB\Statement