结构化查询诧言(Structured Query Language)简称 SQL，结构化查询诧言是一种数据库查询和程序设

计诧言，用于存取数据以及查询、更新和管理关系数据库系统。

结构化查询诧言是高级数据操作诧言，丌要求用户指定对数据的存放方法，也丌需要用户了解具体的

数据存放方式，所以是一种高效的数据输入不管理的接口。结构化查询诧言诧句可以嵌套，这使他具有极

大的灵活性和强大的功能。

在本题中，我们要求选手实现部分比较重要和常见的 SQL 诧句，并且自行设定和完成数据的存储格

式不方式，并且我们丌要求持丽存储，选手可以自由选取存储方式。 -The Structured Query surprised INTRODUCTION (Structured Query Language) SQL, Structured Query surprised words is a database query and programming surprised words used to access the data and query, update, and manage a relational database system. Structured Query surprised Introduction the data manipulation surprised Introduction Ji require the user to specify the method of storing data, Ji require users to understand the specific data storage methods, and so is the management of an efficient data input interface. The the Structured Query surprised Introduction surprised sentence can be nested, which makes him a great deal of flexibility and powerful features. In this question, we ask the players to achieve some of the more important and the common SQL surprised sentence, and data storage format is not the way to set and completed, and we are Ji request held Lai storage, players are free to select the storage.