XML查询计算：执行计划和新操作符。
总计查询计算多组记录的小计。
A totals query calculates subtotals across groups of records.
要查询计算机中可用的处理器，可以使用
运行时库没有机会分析程序并以最优的方式构建查询计算。
A runtime library has no opportunity to analyze a program and structure the query evaluations in an optimal manner.
并添加一个称为Fullname的查询计算的第三列。
A third column containing a query calculation called Full name was also added.
本文针对数据库递归查询计算问题的一个子类——线性递归查询计算问题进行了讨论。
The linear recursive query computation problem is a subset of database recursive query computation problem.
需要特别注意某些xpath函数如exist，因为它们要求具有特定元素的版本才能进行查询计算。
Certain XPath functions, such as exist, need special attention, because they can restrain the query evaluation to a set of versions that have a specific element.
在数据库中以xml格式存储数据之后，可以非常高效地查询该数据，因为在运行时无需执行XML解析来实现查询计算。
Once the data is stored in the database as XML, the data can be queried very efficiently, as the XML is not parsed at runtime for query evaluation.
要满足这个查询，必须计算地理城市中心，因此，需要创建一个函数索引来计算这个值。
To satisfy this query, you must compute the geographical city center, so create a functional index that computes this value.
这些操作共同构成了从源数据开始的一系列计算，最终得到查询结果。
These operations work together to form a series of computations from source data to produce the result of a query.
这将极大地提高性能，因为数据库节约了对相同的查询反复计算执行计划所需的所有开销。
This improves performance chiefly because the database saves all the overhead involved with calculating the execution plan for the same query over and over.
EXPLAIN实用程序会报告执行查询的预期计算资源成本。
The EXPLAIN utility reports the anticipated computing resource cost of executing the query.
有了变量和任务，您就可以轻松计算了，例如计算查询进行的次数。
With variables and assignments, you can also perform easy calculations, such as counting the occurrences of a query.
优化器可以使用数据分布来计算查询中过滤器的选择率。
The optimizer can use data distributions to calculate selectivity for the filters in a query.
可以根据偏差度查询项DEV_DEGREE计算出这个标记项。
Compute this from the deviation degree query item DEV_DEGREE.
还有一个验证方法，就是发出以下查询，计算符合条件的行的实际值。
Another way to validate this is to issue a query as below to count the real value of the qualified rows.
优化器使用UPDATESTATISTICS所生成的数据分布信息来计算查询中筛选器的选择性。
The optimizer USES data distribution information generated by UPDATE STATISTICS to calculate selectivity for the filters in the query.
图4展示了一个在联邦服务器使用嵌套循环连接操作符来计算这个查询的计划。
Figure 4 shows a plan using the nested loop join operations at the federated server to evaluate this query.
您可以看到，有分布统计信息的情况下，DB 2执行查询时需要计算的行数更少。
You can see that DB2 has to evaluate less rows to execute the query when distribution statistics are available.
这些保持不变的数据源查询对象可被模型中的其他查询对象、计算器、以及过滤器所引用。
These unmodified data source query subjects can then be referenced by other query subjects, calculations, and filters within the model.
对多个查询公共的计算可以使用MQT来表示。
Computations common to multiple queries can be represented using an MQT.
检查每个远程操作符是否包含在理论上可由给定数据源计算的查询中的最大部分。
Check to see if each remote operator contains the maximum portion of the query that can theoretically be evaluated by a given data source.
优化器是依靠统计信息来计算可选查询执行计划（QEP）的开销，同时选择出最优的计划。
The optimizer relies on statistics to properly cost alternative query execution plans (QEPs) and choose the most optimal plan.
而粗粒度的糅合方法将分析性知识，如查询、评分、计算、指标和图表叠加到运营应用程序的图形用户界面上。
Coarse-grained mashups overlay analytical insights, such as queries, scores, calculations, metrics and graphs, onto the graphical user interface of the operational application.
函数(2)计算一个SQL查询返回的结果集中的行数。
Function (2) gets the number of rows in the result set returned from an SQL query.
另外，可以按时间、节点或集合计算查询负载。
Additionally, you can evaluate the query load based on the time, nodes, or collections.
按城市计算总销售的查询可以写成
The query to compute aggregate sales by city can be written as
与SHIP1操作符相关的语句表明该标量子查询在Oracle上计算。
The statement associated with the SHIP1 operator shows the scalar subquery being computed on Oracle.
MQT可用于通过预先计算聚合值来增强查询性能。
An MQT can be used to enhance query performance through the pre-computation of aggregate values. For example.
下面，您查看ChompQ . pl在哪里查询队列属性并计算需要删除的消息的数量(见清单20)。
Next, you see where ChompQ.pl has queried the queue attributes and calculated the number of messages to delete (Listing 20).
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