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《Head First SQL》 (Chinese Edition), 2nd Edition
book

《Head First SQL》 (Chinese Edition), 2nd Edition

by Kimberly Fessel
June 2026
740 pages
13h 7m
Chinese
O'Reilly Media, Inc.
Content preview from 《Head First SQL》 (Chinese Edition), 2nd Edition

第 3 章. SELECT 语句:查找信息

本作品已使用人工智能进行翻译。欢迎您提供反馈和意见:translation-feedback@oreilly.com

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先到先得?在数据库中,您很可能需要 检索数据 的频率,往往会比插入数据更高。在本章中,你将深入了解功能强大的SELECT语句,并学习如何 访问那些 。你还将认识WHERE子句,它能帮助你有选择地获取所需数据,并避免显示不需要的行。那么,你觉得怎么样?让我们开始行动,查找一些 SQL 数据吧。

搜索目的地

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艾比需要找到可以开车到达的地方,于是她尝试使用第 2 章中的SELECT语句来查看她的表。

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确实如此。

那个 * 会返回所有数据

这花的时间 太久 ,而且 太繁琐 ,因为你不得不逐一筛选海量的信息。

当你在SELECT语句中使用那个 Asterisk(在 SQL 术语中称为“*”)时,你是在要求关系型数据库管理系统(RDBMS)返回 表中 中的值。

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Publisher Resources

ISBN: 0642572408114