...入 到其它SQL 语句中(此称主查询),并做为其一部分被预先执行,因而子查询也称嵌套查询(Nested Query)或预查询(Pre-Query)。 子查询可应用于如下多种场合: - 在基于未知的条件值进行查询时,可考虑使用子查询提供条件值。
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Another side effect to this scenario is that any form of materialization (pre-calculated aggregates) in the database may be ignored since no fact is included in the query.
此场景的另一个副作用是数据库中的任何形式的实体化(预计算聚合)可能会被忽略,因为查询中不包含任何事实。
Because query results from the [HistoricSales] cube are pre-cached, the performance for queries that are run against the sales data of the entire time period is improved.
因为预先缓存了来自[HistoricSales]数据集的查询结果,所以整个时间段的销售数据执行的查询性能得到了改善。
The database may contain materialized query tables (MQTs), the pre-joined and pre-aggregated tables for DWE OLAP models and cubes.
数据库可以包含物化查询表(MQT),即用于 DWE OLAP 模型和多维数据集的预联结和预聚合的表。
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