说明：  《SQL必知必会》(第4版)SQL是目前使用最为广泛的数据库语言之一。本书没有涉及理论，而是从实践出发，由浅入深地讲解了广大读者所必需的SQL知识，适用于各种主流数据库。实例丰富，便于查阅。本书涉及不同平台上数据的排序、过滤和分组，以及表、视图、联结、子查询、游标、存储过程和触发器等内容，通过本书读者可以系统地学习到SQL的知识和方法。
(SQL is one of the most widely used database languages at present. This book does not involve the theory, but from the practice, explains the SQL knowledge necessary for the readers from the simple to the deep, which is applicable to all kinds of mainstream databases. The examples are rich and easy to look up. This book involves the sorting, filtering and grouping of data on different platforms, as well as tables, views, joins, subqueries, cursors, stored procedures and triggers. Through this book, readers can systematically learn SQL knowledge and methods.)