Bitmap indexes can include rows that have NULL values, unlike most other types of
indexes. Indexing of nulls can be useful for some types of SQL statements, such as
indexes. Indexing of nulls can be useful for some types of SQL statements, such as
queries with the aggregate function COUNT.
位图索引可以让行包含NULL值,不像其它类型的索引。NULL的索引有用的对于一些SQL
语句的类型,比如查询使用COUNT聚合函数
本文深入探讨了位图索引在处理NULL值时的优势,特别是针对使用COUNT聚合函数的SQL查询场景。了解如何利用位图索引来优化数据库性能和查询效率。
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