SQL是计算机世界的语言，在用关系数据库开发报表时，将数据放入数据库以及从数据库中取出来，都需要SQL 的知识。很多人以一种马马虎虎的态度在使用SQL，根本没有意识到自己掌握着多么强大的武器。本书的目的是打开读者的视野，看看SQL究竟能干什么，以改变这种状况。-SQL is the language of the computer world, the statements in relational database development, data into a database and taken out from the database requires SQL knowledge. A lot of people in a so-so attitude in the use of SQL, do not realize that they grasp what a powerful weapon. The purpose of this book is to open the reader' s perspective, see SQL what it can do to change this situation.