什么是SQL Server中的覆盖索引和涵盖的查询？ [英] What are Covering Indexes and Covered Queries in SQL Server?

问题描述

您能解释一下Microsoft SQL Server中覆盖索引和涵盖查询的概念和关系吗？

Can you explain the concepts of, and relationship between, Covering Indexes and Covered Queries in Microsoft's SQL Server?

推荐答案

A覆盖索引是一个可以满足查询中所有请求列而不执行进一步查找聚簇索引的索引。

A covering index is one which can satisfy all requested columns in a query without performing a further lookup into the clustered index.

没有覆盖查询这样的东西。

There is no such thing as a covering query.

看看这篇Simple-Talk文章：使用覆盖索引来提高查询性能。

Have a look at this Simple-Talk article: Using Covering Indexes to Improve Query Performance.

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