In this paper, based-on attribute-cluster, a new spatiotemporal data aggregation query algorithm is proposed.
提出了基于属性簇的时空数据聚集查询算法。
Aggregation query over high rate data streams: basically, most existing aggregation algorithms adopt the approximation technology to obtain the advancement of rate by sacrificing the accuracy.
高速数据流聚集查询：目前已有的聚集算法绝大多数是采用近似技术，以牺牲精度来换取速度的提高。
Cardinality estimation is a process by which the optimizer USES statistics to determine the size of partial query results after predicates are applied or aggregation is performed.
基数估计是这样一种过程：在应用了谓词或执行了聚集之后，优化器使用统计信息确定部分查询结果的大小。
This allows the consumer to not have to query/access multiple data sources and perform the aggregation.
这让消费者不需要查询、访问多个数据源和执行聚合就可以得到自己想要的信息。
Start by generating the query using the first aggregation function (SUM in the example) in the measure's list of aggregations to aggregate the template expression.
先使用度量的聚合列表中的第一个聚合函数(在这个示例中是SUM)对表达式模板进行聚合，产生一个查询。
MongoDB's query engine also makes it very simple to apply aggregation and group functions on your data.
MongoDB的查询引擎也使得对数据应用聚合和分组函数变得非常简单。
MongoDB query results are stored in cursors that provide a range of functions for filtering, aggregation, and sorting including limit(), skip(), sort(), count(), distinct() and group().
MongoDB查询结果存储在提供过滤、聚合和排序等一系列功能的游标中，包括limit()、skip()、sort()、count()、distinct() 和group()。
Aggregation is one of the most important operations in query processing for sensor networks.
聚集运算是传感器网络查询处理中最重要的一个运算。
The paper introduces optimizing data sources to improve the performance of a OLAP system and the methods of optimizing database, aggregation and memorizing client record query.
通过优化数据源提高OLAP系统的性能，文章详细介绍了优化数据库、聚合及采用记录客户查询的方法。
By using the for clause in the after-aggregation detail filter on a non-projected data item, the underlying query automatically projects and groups the item as the outer most column of the list.
通过在一个未投射的数据项上的after - aggregation细节过滤器中使用for子句，底层查询会自动将该项目投射并分组为列表的最外层列。
This paper discusses the understanding on the parallel database from the architecture of parallel database systems, parallel database query, aggregation, sorting, and data reliability.
本文从并行数据库系统的体系结构、并行数据库的查询，聚集，排序及数据可靠性等方面入手，阐述了对并行数据库的认识和看法。
The standard query operator methods that perform aggregation operations are listed in the following section.
以下部分列出了执行聚合运算的标准查询运算符方法。
An OLAP query often needs read-only access of data records for summarization and aggregation.
通常，OLAP查询只需要对数据记录进行只读访问，以进行汇总和聚集。
If you want to create more than one aggregation in the query, repeat steps 3 and 4.
如果要在查询中创建多个聚合，请重复第3和第4步。
A set of conditions in a query that narrow the scope of the data returned. A summary filter is applied after aggregation is complete.
一个在查询条件一套缩小数据范围返回。过滤器的摘要采用聚合后完成。
The simulation results show that, the larger the target window is, the better the performance both the query accuracy and latency of our DWAQ aggregation algorithm presented in this paper is;
仿真结果表明，随着目标窗口变大，本文提出的DWAQ聚集算法在查询准确性和延迟上有一定的优越性；
Because the aggregation operates in the context of the query scope, any filter applied to the query will also apply to the aggregation.
因为聚合工作在查询作用域的上下文中，那么适用于查询的任何过滤器也同样能够适用于聚合。
This algorithm can help users to manage data efficiently during aggregation, classification, prediction, query, understanding and decision-making.
该算法能帮助用户对数据进行有效的融合、分类、查询、分析、理解和决策。
In order to improve query performance, data warehouse usually contains pre-aggregation.
数据仓库通常都包含预聚集。
In order to improve query performance, data warehouse usually contains pre-aggregation.
数据仓库通常都包含预聚集。
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