SQL初学者空值的相关内容

文章 2017-05-02 来自：开发者社区

《SQL初学者指南》——1.8 空值

本节书摘来自异步社区出版社《SQL初学者指南》一书中的第1章，第1.8节，作者：【美】Larry Rockoff，更多章节内容可以访问云栖社区“异步社区”公众号查看。 1.8 空值 SQL初学者指南表中每个单独列的另一个重要属性是，该列是否允许包含空值。空值表示某个特定的数据元素没有数据。按照字面意思解释就是没包含数据。空值不等同于空格或空白。从逻辑上讲，空值和空格要区分对待。在第8章中，我们....

文章 2017-05-02 来自：开发者社区

《SQL初学者指南（第2版）》——1.6　空值

本节书摘来自异步社区出版社《SQL初学者指南（第2版）》一书中的第1章，第1.6节，作者：【美】Larry Rockoff，更多章节内容可以访问云栖社区“异步社区”公众号查看。 1.6　空值表中每个单独列的另一个重要属性是，该列是否允许包含空值。空值表示某个特定的数据元素没有数据。按照字面意思解释就是没有包含数据。然而，空值不等同于空格或空白。从逻辑上讲，空值和空格要区分对待。在第7章中，我们....

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云数据库SQL Server，具有企业许可授权，权限更为开放，引擎功能更为强大。能完美支持Windows平台的.NET架构，支持复杂SQL查询，性能优秀，并有强大的可视化管理工具，帮助您轻松管理数据。

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《SQL初学者指南》——1.8 空值

《SQL初学者指南（第2版）》——1.6 空值

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